Four British companies with a combined market capitalisation of £23.3bn ($41bn) on Monday received takeover approaches in a flurry of activity unmatched since the height of the dotcom boom in 2000.

The bids drove the FTSE 100 index to its best one-day performance in two and a half years, up 2 per cent to 5317.3, as Telefónica, Spain's largest telephone company, agreed to buy O2, the UK mobile operator for £17.7bn including a £3.3bn premium to Friday's share price.