Jacqui Smith on the government's plans to prevent terrorist radicalisation
The Conservatives have accused Home Secretary Jacqui Smith of a "blatant breach" of Whitehall election rules and reported her to the cabinet secretary.
They say she has broken election rules by announcing 300 new counter-terror police officers ahead of May's local elections in England and Wales.
Shadow local government minister Eric Pickles said Labour was in "panic".
The Home Office said it had decided it was appropriate to make a statement on an issue of national importance.
Mr Pickles, who wrote the letter of complaint, said other ministers might also be reported.
He says ministers were told in March to delay any such announcements until after 1 May, when local elections are being held in England and Wales.
Mr Pickles told BBC Radio 4's The World at One: "This is the most blatant breach I've ever seen...
"All the sites likely to receive this additional personnel are up for election."
Mr Pickles added: "To use precious public resources in trying to bolster their [Labour's] poll position - we know they are in a state of panic."
The rules covering the pre-election period, which officially began on 10 April, are a long-established set of conventions set out in detailed guidance from the Cabinet Office before every election. They are not legally enforceable.
It is clear that Labour ministers have intentionally broken Cabinet Office rules in an attempt to create a political smokescreen
Guidance states that "particular care should be taken over official support and the use of public resources, including publicity, for ministerial announcements which could have a bearing on matters relevant to the local elections".
In his letter to Cabinet Secretary Sir Gus O'Donnell, the head of the civil service, Mr Pickles wrote: "It is obvious that both law and order and community cohesion are key issues of political contention in both the local elections and Greater London Authority elections."
The Conservatives say the announcement has broken the convention that Civil Service resources not be used "to attempt to influence elections".
Last month they complained about newspaper advertisements taken out by the government about neighbourhood policing teams - describing it as "political marketing".
Mr Pickles added: "It is clear that Labour ministers have intentionally broken Cabinet Office rules in an attempt to create a political smokescreen.
The Home Office took the view that it was appropriate that an announcement on an issue of national importance should be made
Home Office spokeswoman
"They are trying to hide the fact that police authorities across the country are now axing the number of police officers, whilst hiking the police levy on council tax bills."
He accused ministers of desperation in "trying to salvage a sinking election campaign".
But Chris Huhne, for the Liberal Democrats, said it would be "churlish" to criticise the announcement as a breach of election law, as the money had been announced last year, in the Comprehensive Spending Review.
A spokeswoman for the Home Office said it attached "great importance to adherence to the rules governing elections".
She said it had carefully considered the issue and discussed it with the Cabinet Office, but said the speech was about prevention of terrorism "an issue of fundamental national importance".
"As she made clear in her radio interview this morning, (Ms Smith) believes that this is an issue which transcends party lines and is a response to a serious and urgent threat to our national security."
She added: "The Home Office took the view that it was appropriate that an announcement on an issue of national importance should be made."
There are no formal penalties for any breach of the convention.
But if Sir Gus were to uphold the complaint, it would be embarrassing for the home secretary.
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