Teesport is one of the largest in Europe

Stockbroker Collins Stewart bought PD Ports from Japanese owners Nikko and is also taking on the port's £280m debt.

Collins Stewart - who beat off other possible buyers - plans to float the firm on the Stock Market and say there are already potential investors.

PD Ports, who attracted interest from ABP and Mersey Docks, also own sites on the Humber, Trent and Ouse.

Graham Roberts, group chief executive of PD Ports, said: "This is an extremely exciting moment for PD Ports plc.

'Supportive owner'

"We are coming to the market at a time when our recent investments in container facilities and property development, particularly at Hartlepool, should start to deliver growth.

"Our core business continues to generate stable profits and strong cash flow.

"Nikko has been an excellent supportive owner of the business since 2000, and we now look forward to driving PD Ports' next stage of development and to delivering value to our new shareholders."

The company says it is standing by a £500m joint plan to redevelop part of the harbour at Hartlepool.

Teesport is seen as a profitable alternative to increasingly congested ports in the south of England.