A US bidder will have to hike its offer for the Hampshire firm which keeps the power flowing at Heathrow’s Terminal 5 and Arsenal’s Emirates Stadium after it posted forecast-beating profits.

Power protection firm Chloride, which last month rejected a £723m unsolicited bid from industrial giant Emerson Electric, reported pre-tax annual profits of £41.4m.

The results were at the top end of City forecasts and confirmed analysts’ expectations that Emerson will have to raise its bid to as much as £900m. Its 275p a share approach would need to be increased to about 340p a share, as previously reported by the Daily Echo.

Chloride, which provides bluechip companies with systems to protect against power outages, firmly rebuffed Emerson’s initial takeover proposal in April.

The firm, which employs 60 people in Southampton, failed to mention the bid in its results statement yesterday.

“The only thing I can tell you is that we’ve heard no more directly from them,” finance director Neil Warner said.

Michael Blogg, an analyst at brokerage Arbuthnot, said: “We expect the starting point for a successful offer from Emerson now to be substantially above 300p, which will test the latter’s resolve.

“Emerson may need Chloride to fill a gap, but Chloride does not need Emerson.”

Chloride said it had seen clear signs of a recovery in its core markets and gave a confident outlook for the year ahead after a 16 per cent rise in orders.

Its revenues climbed three per cent to £336m over the past year, although its pre-tax profits dropped five per cent.

With restructuring costs and other one-offs taken into account, profits were 25 per cent lower, at £29.9m.

Chloride has a UK workforce of 374 at offices in Southampton, Aberdeen and Bedford, and worldwide staff of 2,333 across 15 countries.

Emerson, which has a £13.5 billion turnover, believes that a combined group would “create a powerful force in the global uninterruptible power supply market”.

Chloride began trading more than 100 years ago as a battery manufacturer but moved into power supplies in the early 1970s, basing the company jointly in Northam and Hastings, East Sussex.

The two sites were merged into a factory in Eastleigh and then relocated to its current base in George Curl Way in 2000 when the company became a pure power protection business.