The Lib-Dems confirmed they had met Merseyside Police to discuss policing the conference.

A party spokesman said: “Liberal Democrat officials will be working closely with Merseyside Police to ensure a secure conference in Liverpool this year.”

Meetings have also taken place between police authority chair Cllr Bill Weightman and Liverpool city council to discuss the scale of the operation. Cllr Weightman fears if the Home Office does not fund the operation, Merseyside tax payers may have to foot the bill.

He added that the final cost has not yet been worked out.

He said: “It’s still in the planning stage. It depends on the number of delegates, the number of break out sessions.

“It also depends on the likes of Nick Clegg, who requires a higher level of security, because he is a Government minister, and whether any Conservative ministers attend as well – that will add to the cost.

“The Lib-Dems have never been in that position, so it’s taken the Home Office by surprise, so they’re having to look at how they write their policy. What’s taking the time is the bureaucracy.

“I can imagine Whitehall officials going ‘whoops’ when they realised.

“If we don’t get the funding from the Government, it would mean that the tax payers of Merseyside would have to pick up the tab.”

A Merseyside Police spokeswoman added: “Merseyside Police is committed to providing effective policing for the Liberal Democrat party conference to ensure the safety of delegates and residents.

“Operational plans to police the conference at the BT Convention centre in September are currently being developed.

“Discussions regarding the funding for the policing operation surrounding the conference are currently ongoing.”

A Home Office spokesperson said: “We don’t publicly discuss security arrangements.”