Jack Jones of UBS Phillips & Drew is understood to have reduced his forecast from pounds 165m to pounds 157m pre-tax, while David Ireland of Hoare Govett has trimmed his forecast from pounds 165m to nearer pounds 160m.
Last year Williams, which makes a range of DIY products, military bridges and fire-fighting equipment, made pre-tax profits of pounds 168m.
First-half profits were hit by lower deliveries of military bridges and higher interest charges, partly reflecting the cost of a 10 per cent stake in Racal Electronics. Williams sold the stake, acquired during its unsuccessful bid last year, in April.
Trading profits rose by pounds 2m to pounds 82.2m on sales up pounds 23m to pounds 494m. Brian McGowan, chief executive, said the margins, although down from 17.2 to 16.7 per cent, reflected well on the company's management.
Profits from European consumer and building products rose from pounds 26.2m to pounds 32.2m, despite the price war between DIY retailers. Williams is benefiting from its well-established brand names, which include Rawlplug, Polycell and Swish.
The interim dividend was unchanged at 5p, while earnings were down from 10.9p to 9p.
The shares, which have under-performed the rest of the market by 15 per cent so far this year, rose 20p to close at 250p.
The company has net borrowings of about pounds 140m while net assets stand at pounds 420m. It has recently arranged a further dollars 175m fixed-rate borrowings, giving it scope to make acquisitions for cash. The company is keen to expand. Mr McGowan said: 'There are plenty of big groups under pressure from bankers and others who will have to sell businesses.'Reuse content