The industry is rife with speculation that the final job cut total will be 500-600 as staff remain under consultation about plans to deliver big operational savings at offices.

But Britain’s biggest builder today only reconfirmed it was on course to save £30m by 2013 after consolidating its administration support.

Extra cost efficiencies from the looming round of job cuts among white collar construction staff would help deliver an extra £50m saving by 2015.

Balfour Beatty said: “The majority of the benefits of this programme are likely to be delivered in 2013, underpinning margins primarily in UK construction services and support services.”

In the UK, revenue at the construction services arm remained stable in the first five months of the year, helped by a strong performance in the south east.

But Balfour warned UK margins continued to come under pressure.

It added that there were signs of recovery in the US, but “as anticipated, the UK construction market remains challenging”.

In another trading update, Costain today said it had secured £800m in sales so far this year.

It reported a high level of tendering activity in infrastructure, environment and energy and process sectors, which the contractor is targeting.

A quarter of its £2.4bn worth of existing contracts and orders now comes from support services work.

Galliford Try also reported its construction division was trading well in a difficult market.

The construction order book hit £1.6bn in line with last year. Some 80% was secured for 2013, compared to 73% at the same time last year.

Significant project wins included financial close on the £347m Gateshead Regeneration programme, £117m haul of water projects for Anglian Water, Scottish Water and Yorkshire Water, £56m of Partnerships development contracts and £49m in the commercial building sector.