MPs under criticism for distributing largesse to their families now want to extend it further - by allocating perks to long-term boyfriends and girlfriends.

They would be able to travel first class at taxpayers’ expense between Westminster and their constituencies as often as 30 times a year.

The new perk would allow MPs such as Lembit Opik to travel first class with partners. Opik, the Liberal Democrat MP for Montgomeryshire, has been dating Gabriela Irimia, one half of the Romanian pop duo the Cheeky Girls, since 2006. This weekend he said: “I’ll be guided by whatever recommendations are agreed.”

MPs’ husbands, wives and gay civil partners are already entitled to the travel perk. Under the new proposals, MPs would be able to name the person who would qualify for the free tickets.

Girlfriends and boyfriends would be able to travel first class by aircraft, train or ferry. MPs would also be entitled to claim back mileage.

To qualify for the perk, the boyfriend or girlfriend would have to have been nominated by the MP as a beneficiary of their pension. This would rule out all but long-term partners.

The proposal, which is now under discussion, was floated last week by the Members Estimate Committee, following a recommendation by the Senior Salaries Review Body.

It has angered campaigners who claim MPs are wasting funds and abusing the system so that family members can travel to London for recreational trips.

Matthew Elliott, chief executive of the Taxpayers’ Alliance, said: “Every reform of MPs’ expenses seems to involve even more taxpayers’ money. A system including boyfriends, girlfriends, lovers, dates and goodness knows who else would be impossible to administer.”

The change in the rules follows lobbying by unmarried MPs, who claim it is unfair that their partners are not entitled to the same travel allowances as wives and husbands.

Several MPs are in long-term relationships but not married. They include the former cabinet minister Stephen Byers, whose long-term girlfriend, the lawyer Jan Cookson, does not qualify for the travel perk.

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