Members of the Gay Police Association are among tens of thousands of police officers who are taking part in a protest march through central London today.

An estimated 22,500 officers are taking part, a higher number than had been expected. 150 Met officers are policing the event.

The government has said that a 2.5% pay rise for police will be backdated to only 1st December for officers in all parts of the UK except Scotland, where policing is a matter for the country’s devolved administration.

The Police Federation, which represents officers, said the rise is effectively a 1.9% increase. Police are legally unable to go on strike.

A Home Office spokesperson said: “We have a responsibility to ensure pay settlements take into account affordability and consistency with government pay policy, including the maintenance of low inflation.”

All three main party candidates for Mayor of London, the incumbent and Labour candidate Ken Livingstone, Conservative Boris Johnson and Lib Dem Brian Paddick, joined the Police Federation march today.

Until he stood down as the Met’s deputy assistant commissioner in May Mr Paddick was the most senior out police officer in the UK.

“Give the police what the independent pay review says they are worth,” he said in a statement.

Tomorrow MPs will vote on whether to give themselves a pay rise of 2.8% as recommended by the Senior Salaries Review Body.

The Prime Minister has urged MPs to accept 1.9%.