Peter Hain is spending about £60,000 on newspaper advertisements and mailshots in a 48-hour publicity blitz as voting for the deputy leadership begins.

He plans to send almost 1 million leaflets and letters to Labour and trade union members and is negotiating to buy full-page advertisements in the Daily Mirror and Daily Star, aimed at blue-collar party supporters.

The scale of Mr Hain’s spending far eclipses that of rival candidates. It was the clearest sign of the burst of activity before the weekend that will probably decide the outcome.

In addition to a flurry of hustings meetings in London, Liverpool, Cardiff and Oxford over the next few days, candidates will seek imaginative ways to capture attention or win over wavering members and trade unionists. Harriet Harman and Jon Cruddas plan visits to car factories and Hazel Blears will pop into a branch of Tesco in Kensington, West London, this morning to chat with workers.

Alan Johnson will address Labour researchers at the Commons, but Hilary Benn prefers the more innovative method of Skype internet conference calls with potential supporters.

All six have agreed to appear in a “speed-dating” event on Radio 5 Live this afternoon, in which each has ten minutes to put forward his or her case and field questions. Behind the scenes, teams of volunteers are crowding campaign headquarters to canvass by telephone.

The boldest move, however, comes from the Hain camp, which has the largest war chest of the six, at £77,000, the bulk of which has been held back until now. Allies said that most of his financial backers were friends from the antiapartheid movement. His biggest donors are David Williams (£20,000), William Frederick Bottriell (£15,000) and Christopher Campbell (£10,000).

Mr Cruddas took a side-swipe at Ms Blears who, in an interview with The Times, said that his willingness to discuss higher taxes for the rich was electoral suicide in marginal seats. Launching his policy manifesto at a museum of immigration in East London, Mr Cruddas said: “I think it is rather trite to contrast a strategy for key marginal seats versus a strategy for heartlands.”

Labour began to send the first batches of ballot papers to its 200,000 members last night. Trade unions and socialist societies are balloting 3.2 million levy-paying members separately. MPs will have their ballots delivered to the Commons.

The party is posting them second-class to save costs, and they should arrive tomorrow or Friday. Campaign teams aim for a peak in activity on these days based on past evidence that nine in ten voters return their ballot papers straight away.

There was also a burst of activity from trade unions to decide whether to include endorsements of candidates in their mailings to members.

The Communication Workers’ Union executive agreed that it would not back any candidate and abandoned plans to endorse Alan Johnson, previously its general secretary. The decision followed a vote by the union’s conference overturning the executive’s original decision to support Mr Johnson.

Previous party elections suggest that rank-and-file union members often ignore their leaders’ endorsements. But campaign teams believe that a leaflet or letter sent out by union chiefs with ballot papers recommending a candidate could sway voters.

Active endorsements are counted as political donations and costs of leaflets as benefits in kind, although factual statements of a decision by a union executive or political committee to back a candidate are not.

Mr Cruddas, the backbench MP, may be the greatest beneficiary of such “under-the-radar” support, having secured the active backing of the transport workers’ union and Amicus, which are merging to form the super-union Unite and between them have 1.2 million levy-paying members.

Mr Johnson has the support of Unison, Britain’s largest union with 500,000 levy-paying members. It is recommending that members give their second-preference vote to Mr Hain.

The GMB decided this week to support Mr Hain, after hustings with all six candidates. They will send members a letter explaining their decision with their ballot papers. Smaller unions are also backing Mr Hain.

Usdaw, the shopworkers’ union, nominated Hazel Blears, while the only union support mustered by Hilary Benn is from the tiny pottery workers union Unity (former the Ceramic and Allied Trades Union), based in Stoke-on-Trent. It has 9,000 members.

Campaign trail

— HILARY BENN

Tomorrow Conference calls with members/interviews

Friday Meeting Labour members in Staffordshire

— HAZEL BLEARS

Today Visits Tesco in Kensington to meet staff

Tomorrow Foyer project Friday Meets Labour members in Warrington

— JON CRUDDAS

Tomorrow Tours car plant in North West

Friday Visits Labour members in Midlands

— PETER HAIN

Tonight Rally in London

Friday Campaigning in North East

— HARRIET HARMAN

Tomorrow City Hall for antigun crime campaign

Friday BMW factory, Oxford

— ALAN JOHNSON

Today Addresses Labour researchers at Commons

Friday School/college visits

— Who can vote

Labour’s three-part electoral college

380 MPs and MEPs

200,000 party members

3.2m levy-paying members of affiliated trade unions or socialist societies

Times Recommends

• The Times celebrates its 225th birthday
• Heath discussed IMF loan during 1974 crisis
• Britain’s loneliest café opens for business