HMS Mersey returns to Portsmouth after migrant mission

The vessel was deployed to the Strait of Dover on January 3 to prevent an increasing number of migrants from risking their lives making the dangerous 20 mile crossing.

HMS Mersey's mission was to support the UK Border Crossing and French authorities in their response to migrant crossings. 

The navy's involvement was requested by Home Secretary, Sajid Javid, who said it would be an interim measure until two more Border Force cutters, HMC Protector and Seeker, are redeployed from the Mediterranean to UK waters.

Speaking at the time, Defence Secretary Gavin Williamson, said HMS Mersey would '˜help prevent migrants from making the dangerous journey'.

Mr Javid explained: '˜My focus continues to be on protecting the UK border and preventing loss of life in the Channel. For these reasons, the government decided to deploy a navy vessel, HMS Mersey, to support our existing efforts.'

There has been a large increase in the number of migrants trying to corss the Channel to reach the UK.

At least 239 people are known to have reached the UK in small boats since November.

HMS Mersey is normally used to carry out fishing patrols in UK waters and the Atlantic, ensuring boats and trawlers stick to internationally-agreed quotas.

She is due to return to the Strait of Dover later this week to continue to intervene with any migrant crossings.