If elected, he will make strengthening the party's organisation and sharpening its campaigning edge an urgent priority.
Pilot studies on recruitment among political-levy-paying trade unionists has suggested that more than 30 per cent of levy payers have expressed interest in joining the party. In some areas the figure is 50 per cent. The figure is significantly higher than that suggested last year in a survey among the four biggest Labour-affiliated unions, which suggested that about 10 per cent would be 'seriously interested' in becoming full members of the party.
It also follows a perceptible increase in membership as a result of the party's favourable publicity in the wake of John Smith's sudden death, the interest generated by the leadership campaign and the positive appeal of Mr Blair.
Mr Blair has used the campaign largely to position the party on a series of key national issues from economic policy and the welfare state to Europe and the constitution. He will warn on Thursday, if he wins, that the party will only secure an election victory with radical new policies which have a wide popular appeal. He will say those flagship policies will need 'hard work and tough choices' before settling those flagship policies.
But he is also expected to continue the drive for internal modernisation of the party, injecting new professionalism in its campaigning both at headquarters and in the regions. He is said to be unconvinced that the party is realising its campaigning potential and to regard the job of transforming the party's organisation in the country and boosting its recruitment as one of the most important he has to fill under his leadership.
John Prescott, who is competing strongly for the deputy leadership post against Margaret Beckett, has made it clear he would relish a national campaigning role and could see himself as the right man to fill this organisational job if he wins the contest.
The new findings - after pilot studies were pushed through the national expecutive by Mr Blair last year - suggest a big recruitment potential if the party nationally followed Mr Blair's Sedgefield constituency in widening its membership base. Since 1981 individual party membership has declined from a peak of 350,000 to about 260,000 last year.
Leading article, page 13