Contractor Balfour Beatty has invested about £500,000 in construction portal BuildOnline.
Swiss venture capitalist ETF and British Telecom have also put £10m into the venture.

Balfour Beatty managing director Paul Lester brushed off doubts over the wisdom of the move, saying BuildOnline had good prospects.

He said Balfour Beatty's contribution was more a symbol of support than an investment, adding that the £10m from ETF and BT guaranteed its future.

He said: "We didn't want to be aligned with someone that wasn't going to be around for long. We looked at a lot of dotcoms but this is the one we went for because we believe it is on top of it and has got £10m in the bank and we like that."