BUS and rail operator Go-Ahead said the cost of fighting off last year's hostile takeover bid by French consortium C3D had dented profits.

Go-Ahead, the operator of Thames Trains, said C3D's approach had been "wholly unwarranted" and had landed the Newcastle-based company with a £6m one-off charge.

Pre-tax profits for the six months to December 30 were down as a result, falling to £20.1m from £22m last time.

But chairman Professor Sir Frederick Holliday said, while the cost still rankled, Go-Ahead could look to the future with confidence.

He added: "My colleagues and I feel vindicated in our defence of the group's independence as our business strategy unfolds."

Stripping out the one-off charge relating to the C3D bid, pre-tax profits for the period rose 13 per cent to £24.8m, above City expectations.

Operating profits within the company's bus division, which includes services in London, dipped slightly from £14.9m to £14.8m this time.

The figure for Go-Ahead's rail operations was up to £9m, from £5.8m last time.

Go-Ahead said the bus businesses had performed well in the face of significant cost pressures, including higher oil and insurance charges.

But staff shortages continued to be a worry for the firm, particularly in London.

Sir Frederick said: "The shortage of semi-skilled staff in London, largely occasioned by the high cost of accommodation, is limiting the ability of the company and its competitors to respond."

Go-Ahead added the knock-on effects from the rail disruption in the wake of the Hatfield rail crash were likely to continue for some time.

It is planning a series of promotions to attract customers back to its services, which include the Thameslink line from Bedford.

The group also won preferred bidder status for the South Central franchise in October.

Chris Moyes, deputy chief executive, hoped the company could begin running the key London commuter service by the summer.

It has pencilled in £1.5bn worth of improvements for the network, including work to increase capacity on the line from Brighton.

Go-Ahead is set to run the franchise as part of a consortium called Govia which includes French state railway firm SNCF.

Negotiations are currently taking place with the Strategic Rail Authority about the possibility of a 20-year franchise for the service, which will be retitled the New Southern Railway.

Mr Moyes said the company had scoured the country and even overseas to ease the bus staffing crisis in London, which is impacting upon services.

He added the group was "annoyed" about the impact of the approach from C3D: "We finished up with a bill for £6m for something we did not want.