The police investigation into Peter Hain’s failure to declare donations may not conclude for months and officers will have the right to confiscate computers, The Times has been told.

Senior detectives will take weeks to scrutinise the Electoral Commission’s report on the former minister’s campaign to become deputy Labour leader, according to prosecution insiders.

They will then examine public statements made by Labour officials and donors before questioning them and Mr Hain. If necessary, officers will have powers to confiscate computers and documentation belonging to Mr Hain’s former campaign team. This could mean that the inquiry may not conclude before 2009 – hampering the possibility of an early general election for Gordon Brown.

An informed source said: “It will be weeks before Mr Hain is questioned formally – and then much longer before any decision is made about whether to send files to the CPS [Crown Prosecution Service]. We are talking months before the police finish and then some before a decision on whether to prosecute.”

The Scotland Yard team is being headed by Acting Commander Nigel Mawer, head of the Economic and Specialist Crime Unit. His group, also known as SCD6, handles sophisticated fraud cases. Officers investigating the Hain donations will examine allegations that there was a conspiracy to hide the money from the election watchdog.

Inquiries could centre on the Progressive Policies Forum, a think-tank through which £50,000 was given to Mr Hain’s campaign. Those who could be questioned include Phil Woolas, the junior minister who helped to run Mr Hain’s campaign; John Underwood, who set up the think-tank; Phil Taylor, Mr Hain’s former special adviser; and Steve Morgan, his former campaign manager.

Donors to Mr Hain’s campaign may also be questioned. They include Willie Nagel, a diamond broker who lent the Hain campaign £25,000 and gave another £5,000 via the think-tank, and Isaac Kaye, a businessman who gave £14,000 to the think-tank.

Those close to the inquiry are eager to point out that there will not be the same dramatic raids of Whitehall offices that took place during the cash-for-peerages investigation.

“This has been launched under the Political Parties, Elections and Referendums Act 2000, and at worst could result in a fine. Last year’s investigation was under honours legislation and could have led to a lengthy sentence. This will be a lower-key inquiry,” the source said.

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