Candidates fighting to become the next MP for Hampstead and Kilburn have denounced proposals to raise MP salaries as “out of touch” and “unnecessary”, with two of the hopefuls vowing to donate any extra cash to charity should they win the seat in 2015.

The promises came as the Independent Parliamentary Standards Authority (IPSA) – the watchdog set up after the expenses scandal – revealed plans to give MPs an 11 per cent rise in their annual salary to £74,000 in 2015.

Cllr Simon Marcus, Conservative representative for Hampstead Town, and Cllr Tulip Siddiq, Labour representative for Regent’s Park, said they would donate the extra £7,600 to “worthwhile causes”, with both calling the decision “wrong” in a time of austerity.

Liberal Democrat candidate Maajid Nawaz also criticised the proposals by IPSA and said he would “consider” matching his opponents’ pledge but was cautious of making any “desperate campaign promises”.

He suggested a possible solution to the problems caused by changes to MPs’ salaries could be to peg them to a profession of similar standing.

The leaders of all three major political parties have also spoken out against the proposed rise.

IPSA, which does not need support from Parliament to push through the changes, argues that MPs salaries had fallen behind in recent years and were due a one-off boost.

Glenda Jackson, who is stepping down as MP for Hampstead and Kilburn, called IPSA’s proposals “outrageous”.

“It’s a scandal when all other public sector salaries have been frozen at one per cent and when the standard of living for many people is falling,” she said.

“I hope the rest of Parliament is as outraged as I am.”