Two Albanian illegal immigrants were still missing last night – with the authorities still unsure whether or not they jumped overboard from a passenger ferry.

It has been revealed that the pair were among a group of 13 being deported after arriving on an earlier ferry sailing and having been refused entry into the UK.

Minutes after the Stena Britannica set sail from Harwich for the Hook of Holland, Thames Coastguard received a Mayday call reporting that two men had jumped from the vessel.

A massive air-sea search and rescue operation was launched off Felixstowe with about 20 vessels, including three RNLI lifeboats along with tugs, a pilot cutter, and fishing boats, plus the Suffolk Constabulary helicopter and a rescue helicopter from Wattisham Airfield, taking part.

On shore, land-based Coastguard rescue units from Felixstowe and Shingle Street searched the coastline between Old Felixstowe and Landguard, and the banks of the River Orwell and Deben estuaries.

Although two jackets were found floating on the sea, there was no sign of the men, despite a thorough and precisely-targeted search using the latest technology and techniques.

A Border Force spokesman said yesterday: “On Wednesday, 13 individuals who had arrived on a ferry at Harwich were refused entry to the UK by Border Force officers.

“They were returned to the Netherlands on a later ferry. Upon its arrival in the Netherlands only 11 of the 13 were accounted for by the Dutch authorities.

“We are aware of reports that two people jumped from the ferry after it departed Harwich and Border Force assisted police and the coastguard with their search operation.

“The same vessel returned to the UK this morning and Border Force officers carried out extra checks on vehicles as they arrived.

“Two Albanian nationals remain unaccounted for.

“The matter is now the subject of a missing persons inquiry, which is being led by Essex Police.”

The Dutch Royal Police are also carrying out investigations in the Netherlands and believe the immigrants could be part of an international human smuggling operation.

They plan to interview those who were returned before deporting them to their homeland.

Stena Line would not comment on the identity of the missing passengers, but said the company did everything possible to ensure its North Sea services are not used by people attempting to gain illegal entry into the UK.