W. S. Atkins vowed to stick with Metronet for “the long term” yesterday, after the Tube maintenance company’s first loss dragged shares in Britain’s biggest engineering consultancy down by 6 per cent.

The profit contribution from Metronet, a joint venture charged with the 30-year upgrade of the London Underground, was down £1.4 million on the first half of last year — it produced a loss of £0.4 million compared with a £1 million profit previously.

Problems at Metronet overshadowed a near 10 per cent rise in WS Atkin’s first-half pre-tax profits to £30.9 million and a one-third increase in the dividend to 6p. Shares in the engineering group fell 57p to 841p.

The heavily criticised Metronet — a joint venture between W.S. Atkins, Balfour Beatty, Bombardier Transportation, EDF Energy and Thames Water — has come under increasing pressure over maintenance delays. This week it was blamed after maintenance work led to chaos on the Tube network. Last week it was criticised by Ken Livingstone, the London mayor, after a report by the public-private partnership arbiter said that Metronet had failed to peform “in line with the required standard”.

Keith Clarke, the WS Atkins chief executive who also chairs Metronet, defended the joint venture and said the project was “not one we think we should walk away from”.

He told The Times: “We believe we need to be there for the long term. At Atkins, we are committed to assisting Metronet in making this a success.

“We are working with all of Metronet’s stakeholders to enable Metronet to become economic and efficient overall.”

However, he warned of a “slow” recovery and stressed the need to improve the supply chain so that Metronet could finish its first phase by 2010.

W.S. Atkin’s profits from continuing operations and excluding Metronet were 18 per cent higher at £31.3 million, driven by robust growth in its Middle Eastern operations, growth in its design division and recovery in the UK rail market.

Revenue in the first half was up 17 per cent at £605.5 million. The company said lower margins were caused by a £2.5 million increase in pensions costs.

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