Costain was the biggest winner among the construction and building materials sector last week.

Shares in the company rose by almost 9% to 53.75p after it won a $1.6bn (£900m) contract in Iran. The firm is part of a joint venture that has been named lead contractor for a four-year programme to build a gas treatment facility for the National Iranian Gas Company.

The win illustrates a wider industry trend for contractors to turn to the energy and utilities sectors to diversify their business. Stuart Doughty, Costain’s chief executive, says the contract is part of a plan to develop an international gas processing business, and the company has had several notable wins in the water sector so far this year.

Carillion also had a good week. Shares in the company rose 6% to 269p. This is not a surprise: the contractor has performed solidly since the start of 2005. It has done particularly well since May, thanks to project wins in the public health and education sectors.

The news was less remarkable in the rest of the sector. Among the worst performers was Mowlem, shares in which dropped 4% to 181.5p. Its share performance in 2005 forms a striking contrast with that of Carillion, as its shares have followed a bumpy course, with a particular low point in May and June.

Berkeley’s share price benefited from the announcement that it had sold off its Crosby Homes subsidiary to Lend Lease (see page 20), as well as a decent set of annual results. Shares rose 3.3% to 914p.

Wilson Bowden also had a good week, up 3.5% to 1159p, ahead of its trading update statement, made on Tuesday this week.

In the support services sector, shares in consultant White Young Green rose 5% to 295p, whereas John Laing dropped almost 5% to 254.75p. Atkins fell 2.3% to 670p after it revealed last week that it had set aside £3m to pay for missing its deadlines on station improvements on London Underground.

Amec’s shares moved upward by less than 1% to 349.25p, despite the news that it bought NNC, a company that specialises in nuclear services.

The All-Share Index remained unchanged at 2544 last week while the Construction and Building Materials Index rose 0.9% to 3576.

Angela Monaghan is business editor