Britain's other Fleet

HMC Seeker might look like a vessel of the Royal Navy however this is not so
as evidenced by the fact she is wearing a blue ensign and not the white ensign

The United States Coast Guard is sometimes thought of as a sort of second navy for the USA. Although often regarded as a Search & Rescue organisation it is also a law enforcement organisation and protecting American waters from smugglers, piracy and other criminality as well as being an official branch of the armed forces. The United Kingdom in contrast does not quite have an equivalent. The UK does have Her Majesty's Coastguard which is a safety and search & rescue authority and the Royal Fleet Auxiliary which is a fleet of civilian maned vessels owned by the Ministry of Defence. However its already considered a branch of the Naval Service and its role is to support Britain's interests and Armed Forces logistically rather than conduct naval activities such as intercepting and boarding vessels. In regard to law enforcement the vessels of the Border Protection Squadron of the Home Office's Border Force is Britain's closest equivalent.
The vessels of the Border Force trace their history back to various revenue and customs cutters (a cutter originally being a term for a sailing vessel designed for speed rather than capacity) in the 18th Century to tackle illegal smuggling. The Border Force fleet acknowledges this history calling their vessels cutters to this day; the prefix before the name of the largest Border Force vessels is HMC meaning "Her Majesty's Cutter".

Cutters are principally to board ships suspected of illegally breaching Britain's borders e.g. smuggling which could mean everything from smuggling in French beer to avoid tax to more serious crimes such as drug smuggling or human trafficking, and are at sea 24/7 as explained in this video produced for the Royal Yachting Association.

The current fleet consists of about eleven vessels which vary in size from the 20m RIB Coastal Patrol Vessel like that shown in the above clip to the Telkkä-class Cutter. The total crew compliment across the fleet numbers roughly 120 Border Force officers spread across fleet who normally rotate between spending two weeks on duty and two weeks off duty. This way there are at least five fully operational cutters on duty around the UK at anyone time.
The vessels of the Border Protection Squadron usually operate in the waters around the United Kingdom however they can and have been sent further afield. In 2015 for example HMC Protector and Seeker were deployed alongside Royal Navy and Royal Fleet Auxiliary and other European Customs, Coast Guard and Naval vessels in the Mediterranean to assist in the Migrant Crisis, for this the normal crew compliment was bolstered with a detachment of Royal Marines. Whilst there the two ships helped rescue 1650 refugees and apprehended 26 people traffickers.  As this interview by the Gibraltar Broadcast Corporation details

Boarder Force vessels sail under blue ensign as defines ships in state service sometimes defaced with the badge of the Boarder Protection Squadron.

ensign worn by some Border Force vessels

The badge features a red roundel with the text "Border Protection Squadron" within this badge is a red portcullis on a blue and white wavy field. The badge is ensigned with the St Edward's Crown. This badge is often displayed on the superstructure or cabin of cutters and offshore patrol vessels, although formally the variant of the Royal Coat of Arms used by the Home Office was used in the latter role and this might still be the case on some cutters. Traditionally customs cutters flew a distinguishing pennant. Although such decorations were the sole right of a ship at war the Admiralty turned a blind eye to this providing they were distinct from Royal Navy pennants. I am not sure if Border Force cutters continue this tradition however I have noted in some clips and images that some cutters seem to have a pennant like flag flying from the jackstaff.
The Border Force Fleet is as follows:

UKBF 42m Customs Cutter

These vessels are a variant of the Damen Stan 4207 Patrol Vessel built by the Dutch Damen Group which has provided similar vessels for the Royal Bahamas Defence Force, Jamaican Defence Force, Mexican Navy and Venezuelan Navy among others. Damen's design includes the ability for an emplaced cannon and while at first sight it appears that the Boarder Force vessels of this class also feature one, it is in fact a water cannon. Border Force personnel are not armed with firearms, but can call on ships and personnel of the Royal Navy and National Crime Agency for firearms support. These cutters are 42 metres long hence the class name. The ships of this class are:

HMC Seeker

HMC Seeker in Belfast Lough in 2009
Attribution: Albert Bridge, Wikimedia Commons

The oldest cutter in current service Seeker was built in 2001 for what was then HM Customs & Excise later HM Revenue & Customs whose fleet was later absorbed into the UK Border Agency in 2008 which in turn gave way to Border Force in 2013.

As such she has sailed under at least three variants of the blue ensign and had three different prefixes before her name; HMRC "Her Majesty's Revenue Cutter" HMCC "Her Majesty's Customs Cutter" and latterly simply HMC. Seeker was one of two Border Force ships sent to the Mediterranean to take part in Operation Triton.

HMC Searcher in Weymouth in 2016
Attribution: Richard Symonds, Wikimedia Commons

HMC Searcher 

Built in 2002 for what was then HM Customs & Excise which became HM Revenue & Customs in 2005 and transferred to the Border Agency in 2008. This fleet was inherited by Border Force when the former was dissolved in 2013. Like her sister Searcher has had the same changes of prefix, colours and livery.

HMC Vigilant

HMC Vigilant outside Weymouth
Attribution: Brian Burnell, Wikimedia Commons

Vigilant is the latest of a number of vessels of British revenue services to bear the name. The first HMRC Vigilant being built in 1901 followed followed in 1921 when the former HMS Esther was acquired and renamed, This vessel was the sole official customs cutter in service in UK waters in the 1920s. The last Vigilant before this bearer of the name was acquired in 1947 and like her processor was a former warship, HMS Benbecula and has the distinction of having the first ever live outside TV broadcast from a ship being made on her in 1950. 

The current Vigilant was built in 2004 for HM Customs & Excise and has the same history as her class sisters.

HMC Valiant

HMC Valiant entering Malta's Grand Harbour in March 2018
Attribution: Estormiz, Wikimedia Commons

 Launched in 2004 Valiant is the last ships of the UKBF 42m Customs Cutter class to be built. The ships history mirrors that of her classmates but has the distinction of conducting the single largest seizure of Class A Drugs in the United Kingdom. this happened on 23rd April 2015 when along with the HMS Somerset she intercepted the Tanzanian flagged tug 'Hamal' in the North Sea 100 miles off Aberdeen, and seized over three tones of cocaine.

Telkka Class Cutter

Border Force operates one vessel of this class and that is the HMC Protector. Protector originally named Tavi was built in 2002 for the Finnish Border Guard. She served the Finnish until 2013 when she was acquired by the British Border Force to replace the ageing HMC Sentinel which was withdrawn from service. She was commissioned and named HMC Protector in 2014 as this Home Office video shows:

Protector along with Seeker were deployed on Operation Triton in 2015 helping rescue 1650 refuges. 

20m RIB Coastal Patrol Vessel

Current stats show that Border Force operates around six 20 metre RIBs these smaller vessels are not designed to stay at sea like the larger cutters but operate out of smaller ports and harbours of which the British coast has many. There are eight vessels of this class were acquired post 2015 and bought from BP suggesting their purchase was in response to a shortage of small vessels with the ability to respond to upsurge of migrants attempting to enter UK illegally by crossing the English channel in small boats. Information is not readily available on all these vessels but we know through vessels appearing on marinetraffic.com and names mentioned in news reports that there are atleast six named vessels. There are Her Majesty's Coastal Patrol Vessels Active, Alert, Eagle, Nimrod, Hunter and Speedwell. All were built by Holyhead Marine. Information available on the following vessels: 

HMCPV Active

Built in 2006 she saw service with BP as a rescue boat operating in conjunction with a larger offshore support vessel. She was initially named 'David' and was acquired by Border Force in 2016

HMCPV Eagle

HMCPV Nimrod  in Underfall Yard Britol
Attribution: Keir Gravil, Wikimedia Commons

Eagle originally named Ian was an autonomous Rescue and Recovery craft opertated by BP. Built in 2006 she supported BP projects in the North Sea. She operated as a daughter vessel of a larger offshore support vessel acting as mother ship. Acquired by Border Force and renamed Eagle in 2016.

HMCPV Nimrod

Nimrod was originally named Euan and like her sisters was one eight rescue boats bought from BP. She entered service in with Border Force in 2016.

High Speed Craft

BF Hurricane entering Dover Harbour
Credit: J-Peg/FleetMon

Very recently it appears the Border Force have acquired a catamaran vessel, with pictures of the BF Hurricane appearing on news websites. BF Hurricane appears to have been acquired to assist in the influx of migrants attempting to enter the UK illegally by crossing the English Channel. It was one of two 25m vessels built by Aluminium Marine Consultants for the marine engineering firm CWind. Originally chartered for four years to the energy company Vattenfall under the name Hurricane Tow it is unclear if Border Force has purchased the vessel outright or is simply chartering it from CWind for the upsurge of illegal channel crossings in the Summer of 2021

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