A directly elected mayor of Birmingham could end up demanding a £200,000 salary plus the cost of running an office and staff at huge expense to the taxpayer, it has been claimed.

Yardley MP John Hemming, one of the leaders of the “No” to a mayor campaign, has called upon potential candidates to confirm that they will not be demanding higher pay than the current leader of the council Mike Whitby, whose allowance is now £66,000.

The debate on whether the city should be run by a Boris Johnson style mayor is hotting up with just three weeks to go until the referendum.

A key criticism from the “No” campaign is the cost of a mayor at a time of austerity and council cutbacks.

Mr Hemming pointed out that in Leicester, where Sir Peter Soulsby became mayor last year, the initial plan was to give him the same salary as the chief executive, some £100,000 a year, in view of the status of the mayor. Later Sir Peter’s pay was reduced to £65,000.

The MP said: “The original proposal for Leicester was based upon the salary of the chief executive. If the proposed Birmingham Mayor was paid at the same rate as the chief executive that would mean paying the Birmingham mayor something of the order of £200,000.

And he added that Mayor of London Boris Johnson has a staff of about 25 political advisers on the city hall payroll.

He said: “The country is short of money at the moment. Having a directly elected mayor will increase the costs. We need to know how much the candidates will be paid.

"It is, therefore, important to know the views of those who wish to have the job how much they think it should pay and also what the costs of the private office would be.

“As someone who has suggested that you are interested for standing for such a post, in the event that the voters of Birmingham decide to have it, I have a question.”

One declared candidate Gisela Stuart said: “It is a disingenuous argument from Mr Hemming.

"Like Sir Peter Soulsby I would say that it is not my job to set the mayor’s salary and leave that to the independent remuneration panel which advises on councillors’ pay.”