Shares in Scottish & Newcastle soared last night amid fierce speculation that Scotland could soon lose another stockmarket-listed heavyweight.

Some £600m was added to the value of the Edinburgh-based brewers, Scotland's third-largest industrial company, on the back of City rumours that Dutch rival Heineken is poised to launch a takeover bid.

Shares in S&N, which brews Foster's, Kronenbourg and Baltika beers, climbed as much as 15.4% in early trading before closing last night up 12.1% at 595p.

The company was the fastest-rising stock on the blue-chip FTSE 100 list of leading shares, ending the day valued at £5.6bn.

The climb appears to have been partially spurred by talk of consolidation in the drinks industry at a conference in Dublin on consumer products.

Denmark-based Carlsberg, with whom S&N co-owns the giant Baltic Beverages Holding business, was also cited as a potential suitor.

S&N has no big, dominant shareholder such as Heineken, Carlsberg and Belgium-based InBev, and is periodically touted as a takeover candidate. South African giant SABMiller has also been named as a potential suitor.

A takeover of S&N would almost inevitably see a major corporate headquarters disappear from Scotland, following the company's highly symbolic closure of its historic Fountainbridge brewery in Edinburgh in mid-2005. S&N later moved its headquarters from Murrayfield to St Andrew Square in the centre of the city.

Next month S&N will become the second-biggest industrial - behind Scottish & Southern Energy - assuming that Spanish energy giant Iberdrola completes its takeover of Glasgow-based ScottishPower. ScottishPower shareholders meet in Glasgow today to vote on that deal at an extraordinary general meeting which is expected to be a formality. Drinks industry analysts suggested that Amsterdam-based Heineken could face competition problems with a bid for S&N, given overlaps in the French and Russian beer markets.

Carlsberg, meanwhile, might be deterred from lodging a bid when at some time in the future it might obtain a friendly merger with S&N on favourable terms.

A consortium bid would also be difficult, given intense rivalry in the brewing industry.

The dramatic rise in S&N's share price also needs to be put into context. In February more than £200m was wiped off the company's market value in one day after the brewer warned that a UK-wide smoking ban will slash 2007 profits by £10m.

S&N said then that it is also considering job cuts, after announcing a further £50m of planned cost savings over the next three years. The company said the savings will be split equally between its international operations and the UK, where it employs 4500.

S&N and Heineken declined to comment.