The independent survey, carried out by the property consultants Healey & Baker, is expected to value Bilton's portfolio of mainly industrial properties at around 340p per share, more than 15 per cent above Slough's cash and paper offer of around 294p a share.
City analysts believe that the survey will strengthen Bilton's case that Slough is trying to buy the company on the cheap and will force the company, led by Sir Nigel Mobbs, to consider an increased bid.
The publication of the document will also spell the final deadline for a number of potential bidders, believed to include MEPC and Brixton Estates, to mount a counter-offer for Bilton, a sleepy property group virtually controlled by a family trust.
Slough, which controls around 9 per cent of Bilton's shares, is thought to have the financial strength to increase its bid, but industry experts doubt whether Sir Nigel would take part in an auction for Bilton against MEPC or Brixton.
Slough supporters point out that most bids for property groups are pitched below the net value of their assets.They say that Bilton shares, which closed at 300p on Friday, have been trading below asset value for a considerable time and note that Slough's offer represented a 39 per cent premium to Bilton's share price.
Slough and other potential bidders will be keen to know Healey & Baker's valuation of two controversial fishing and shooting estates in Scotland and Oxfordshire.
In its offer document published last month, Slough claimed that the estates had "failed to generate any meaningful net income for the past two years" and said that Bilton's joint managing director, Ron Groom, was a "keen shooting enthusiast and enjoys using these facilities".
Bilton has always maintained that its directors use the estates at their expense and that the properties are let on a commercial basis.
Today's revaluation will mark a new phase in the war of words between Slough and Bilton. In the sharpest clash between the two companies, Slough accused Mr Groom and the company secretary, Priya Ponnaiyah, of a conflict of interest because they sit on two trusts which control the company through a complex web of cross-holdings.Reuse content