Supermarket giant Morrisons will start trading tomorrow as one of Britain's top 100 businesses.

The Bradford firm's inclusion in the FTSE-100 index was confirmed by the London Stock Exchange today.

The FTSE-100 is seen as the benchmark for share movements in the whole of the stock exchange.

Founded in 1899 by William Morrison, the company's move to the top level comes after five years of rapid growth which has seen it notch up a market value of £3.2 billion.

Speculation about the FTSE move by traders last week saw the price of Morrisons' shares shoot up by 12p to 210p. A further 4.5p rise today took it to 214.5p.

A spokeswoman for the Stock Exchange said: "Computer services company Sema was taken over today by US group Schlumberger, effectively making two companies into one and leaving a gap in the FTSE-100.

"Morrisons supermarkets was rated as the highest-ranking market company outside the FTSE-100 at close of trade on Friday night, so I can confirm that they will join the FTSE-100 as of tomorrow morning."

Other successful firms, including medical equipment group Smith & Nephew, had also hoped to be "promoted" after enjoying similarly dramatic share rises.

Run by chairman Sir Ken Morrison, son of William, Morrisons has enjoyed a 32-year unbroken record of growth in sales and profit.

From its origins as a Bradford egg and butter merchant, the firm set up market stalls and, in 1958, opened a small city centre shop.

Its conversion to a public company in 1967 saw it over subscribed 174 times, with more than 80,000 investors trying to purchase shares.

The company has picked up a string of industry awards, and was named Multiple Retailer of the Year and Off Licence of the Year in 2000.