Voters in ten English cities will decide on 3 May whether to have a directly-elected mayor but a report out today raises concerns over the lack of clarity in what powers a mayor would have.

Professor Keith Grint, who wrote the report for Warwick University, told the Today programme's James Naughtie that part of their concern is that people are unclear of what they are actually voting for.

He went on to say that the salary of a mayor is also unclear and there is no system to organise this and that the substantial salary that would most likely be called for would "aggravate" a lot of people but without it we would go back to a "19th century" political system where subsidiary incomes would be sought out.

Professor Grint said the scrutiny issue and possibility of corruption should also be taken into account.

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