It has also turned down Conservative appeals for an independent commission to investigate the matter.

The issue of referendums was raised in the Commons during a backbench debate, by the Conservative MP for Mid Bedfordshire, Jonathan Sayeed.

A supporter of Scottish devolution cheers the result of one of Labour's four referendums

Mr Sayeed said there had been just eight referendums over the last 25 years but that half of that number had taken place during the present government's first year in office.

He accused the government of trying to "bushwhack" Parliament by side-stepping its conventions and putting power directly in the hands of the electorate.

Mr Sayeed said: "Referendums are not a substitute for parliamentary democracy and must only be used sparingly. This is the place where we argue things out. They must only be used to advise Parliament, not dictate to it or coerce it."

Since Labour came to power in May last year, it has staged referendums on devolving central government power in Scotland, Wales, Northern Ireland and London.

Criticism of the government's multiple use of referendums was not confined to the Conservative benches.

The former political journalist and now Labour MP, Martin Linton, said it was vital for proper debate to take place before any referendum. That had not happened before the vote for a London mayor and assembly, he claimed.

He was joined in his criticism of the London poll by Richard Ottaway, the Conservative MP for Croydon South, who said it had been a case of how not to hold a plebiscite.

Replying to the debate the Home Office Minister, George Howarth, defended the role of referendums saying they gave the people an important voice on constitutional issues.