The misery at border control at Heathrow looks set to continue after unions representing immigration staff gave notice of their intention to strike today.

The Immigration Services Union has told the government that its members will walkout next Thursday in a row over pensions.

The union represents more than 4,500 immigration staff and any industrial action is expected to hit Heathrow as well as Gatwick among other airports.

The London Evening Standard reported Lucy Moreton, deputy general secretary of the union, as saying:

“We don’t want to cause disruption, but if the Cabinet Office continues to ignore our concerns over pensions then that is what we are going to do. We have hundreds of members at Heathrow so it will have a significant impact.”

Another union representing immigration staff has also signalled its intention to call industrial action.

The Public and Commercial Services Union’s spokesman Richard Simcox said: “We will be striking and it will either cause more delays or lead to untrained staff waving people through without proper checks.”

The pensions row centers on a proposal to bring in a flexible retirement age, which the unions say could see their members working longer before retirement.

Immigration minister Damian Green said: “This strike is completely unnecessary and we believe the public will find it unacceptable if unions push ahead.

“The security of the UK border is of the upmost importance and we will use tried and tested contingency plans to ensure we minimise any disruption caused by planned union action.”