More than 50,000 residents of Hull bought shares in Kingston Communications at their sell-off price of 225p.

Hull's best known landmark is the Humber Bridge

In total 27.2m shares being sold off by the council-owned enterprise were allocated to staff and residents of the region.

And after the sharp rise in trading in London, the combined holding had gained �18m in value by the close of business on Monday.

The maximum allocation for individual investors was �5,000 worth of shares - which by close of business on Monday were worth �6,250.

The windfall is only on paper at the moment as most individuals will have to wait for share certificates to arrive before having the chance to cash in their shares.

With the average holding being about 560 shares the average profit on the day for the 52,000 Hull residents who applied for shares was about �370.

One billion

More than 700 Kingston staff also more than doubled their money by taking up the chance of buying �1,000 worth of shares - with a matching allocation given to them of shares from the firm.

The successful launch also has benefits for the local council which retains a 49% stake in a company which is now valued at about �1bn.

The eventual flotation price was at the very top end of the range outlined by the council's advisers in June, valuing the company at �788.6m.

The huge popularity of the sale among the public and institutional investors meant demand far exceeded supply of the stocks.

Kingston upon Hull council is retaining nearly half of the shares in the company, but raised around �260m for its coffers.

Chief executive Ian Crookham said: "We are very, very pleased with the success of the float.

"I don't think anybody thought it was going to be quite as successful as it has been."

The council is now beginning the process of deciding how much of the money to spend on infrastructure projects such as schools and housing.

The majority will be invested to provide an annual income.

Its phone boxes have always been distinctive

Kingston began its operations in 1904 as the Hull Corporation Telephone Department and is known for its trademark white telephone boxes.

It was the last of the 13 local authorities who were awarded operator licences to still be in the public telephone business. Local calls can be made all day for only 5.5p.

The company boasted Britain's first fully digital network as long ago as 1987 and in 1996 established an Internet service provider.

But Kingston wants to expand its network and invest more in services for business customers. It has decided it needs stock market money to pay for the growth.

Takeover target

UK float specialists said that there were a number of reasons for its rise - and, they say, its rosy future.

"Imagine you are a US fund manager with 15 Internet and telecoms offerings on your desk with some asking for ridiculous valuations of �2bn on companies that are barely two-years-old and then you have a 97-year-old telecoms group going for three quarters of a billion. Which would you pick?" said one new issues expert.

Kingston plans to expand across the UK by setting up telecoms services for business customers.

Shares are up on expectations that it could end up becoming a bid target for the likes of Deutsche Telekom or France Telecom - being seen as what analysts described as a perfect bridgehead to the UK market.