Saltaire-based electronics business Filtronic is the second best performing technology firm on the stock market this year.

The business has seen its share price rocket more than 350 per cent in the last ten months as confidence has recovered in the technology sector.

It marks a remarkable transformation in fortunes for the company, which has endured a rollercoaster ride on the stock market including a slump from £25 to 25 pence in the space of 12 months.

Since hitting the floor last year, its value has steadily climbed again in line with a general recovery in the sector.

And investors have been in buoyant mood since an announcement last month that a major mobile phone company has signed a contract which will see Filtronic supply new technology for its base stations.

The new units, developed at Filtronic's Newton Aycliffe plant, contain high power transistors and have been described as a "seismic technology shift". Today chairman Professor David Rhodes said the recent rise in the share price had to be seen in the context of the dramatic slump from its £25 peak.

"We have announced some significant new developments recently and people are beginning to see what that means," he said.

"All I can say is that, relative to our peers in the United States, we are still somewhat undervalued as a company.

"We are only back at a level which is just above the mean of the value when it fell from £25 to 25p."

Michael Coleman, an investment partner at Leeds stockbrokers Redmayne-Bentley, said the technology sector had been a victim of both over-optimistic and pessimistic valuations by analysts.

He questioned whether the dramatic 350 per cent rise in Filtronic's share price was sustainable but admitted the company had been strongly undervalued at its lowest point.

Shares in Filtronic were trading at 382.5p early today.