AER LINGUS is planning to open a base at Gatwick Airport in London next spring, offering short-haul flights to continental Europe.

This will be its first base outside the island of Ireland. The airline will announce the move in the coming days, possibly at a joint press briefing in Dublin and London early next week to launch its defence document to Ryanair's latest takeover approach.

Aer Lingus is also expected to restore the Shannon-to-Heathrow link that it scrapped a year ago amid much controversy.

It is understood that Aer Lingus will base three aircraft at Gatwick and will initially operate short-haul routes to seven destinations in Europe, including Malaga, Munich and Zurich.

The airline is also believed to be looking at offering transatlantic flights from Gatwick, but this would be some time off. Its initial focus will be on short-haul services offering low fares. Gatwick is used by a number of charter operators, flying to holiday destinations in Europe and the Caribbean.

Aer Lingus already operates from Dublin to Gatwick, which lies to the south of London. It also operates flights into Heathrow.

Aer Lingus has been planning to open a UK base for some time as its first move outside Ireland.

It sees this as a crucial step in its growth strategy as an independent airline and as it seeks to defend Ryanair's €748 million offer.

Aer Lingus is believed to have considered a number of locations in Britain for a base, including Birmingham, Glasgow, Edinburgh and Manchester.

Just 12 months ago, it opened its first base outside of the Republic by offering flights from Belfast.

The airline created a storm at the time by axing its Shannon-to- Heathrow flights in favour of Belfast. It is understood that the Shannon-to-Heathrow connection will be restored.

Aer Lingus operates 42 aircraft from Dublin, Cork, Shannon and Belfast, 33 on short-haul routes.

In its €1.40-a-share bid, Ryanair has committed to adding 33 new aircraft to Aer Lingus's short-haul fleet by opening bases in the UK and mainland Europe. Aer Lingus will no doubt hope its decision to open a base in Gatwick will dilute this part of Ryanair chief executive Michael O'Leary's offer.

Separately, it is understood that Ryanair has written to Minister for Transport Noel Dempsey seeking a second meeting about its offer for Aer Lingus. Ryanair has also written to the employee share ownership trust (Esot), which owns 14 per cent of the airline, and telecoms entrepreneur Denis O'Brien to seek meetings to discuss its offer for Aer Lingus.

Mr O'Brien, who has previously publicly opposed Ryanair's proposed takeover of its Irish rival, is believed to own about 2 per cent of Aer Lingus, although its share register reveals only that he holds 0.9 per cent of the airline's stock. Mr O'Brien could, however, hold shares through other vehicles.

Aer Lingus and Ryanair both made presentations on the takeover offer to the Oireachtas transport committee yesterday morning. Mr O'Leary said Ryanair's guarantees over Aer Lingus's Heathrow slots, a reduction in fares and a scrapping of the fuel surcharge forever were real.