Archangel Informal Investment, the angel investment network, shrugged off growing concerns about the credit crunch to record a sharp increase in investment activity in 2007.

The latest annual review for Archangel shows the syndicate invested £8.4m in firms with high growth prospects, compared with £5.2m in the preceding year.

Archangel also placed bigger bets, investing an average of £560,000 in each of the 15 firms it supported, up from an average of £433,000 for 12 firms in 2006.

The syndicate invested an average of £1.2m in the three firms added to its portfolio. These included Vitrology, the biochemical research firm. Archangel invested an average of £213,000 adding three firms to its portfolio in 2006.

The increased deal sizes may reflect the fact that after recruiting more members during 2007, Archangel can now draw on the resources of more than 100 wealthy backers.

Following the introduction of the Scottish Co-investment Fund in 2003, the public sector has taken more of the risks of investing off angels' hands.

John Waddell, chief executive of Archangel, said: "We continue to develop our relationships with Scottish Government agencies, in particular Scottish Enterprise and its three investment arms, the Seed Fund, the Scottish Co-Investment Fund and the Scottish Venture Fund."

He said there was "evidence of nervousness" on the part of potential trade buyers because of the current financial turmoil, but he had seen "some interest on the part of potential acquirers of Archangel companies".

While Archangel had not realised any investments in 2006 or 2007, Waddell said 22 of the 29 firms in its portfolio had "real promise".