Speculation about a potential merger of the two Luton-based airlines first surfaced around six months ago, but the Sunday Times claims easyJet is again pondering a bid for Monarch.

Such a deal which would give easyJet an extra 4% of the slots at Gatwick, where it remains the biggest carrier.

Monarch was close to collapse only two years ago, but an exit from long-haul and charter flying and a cost-cutting and redundancy programme have brought it back into profit.

In autumn 2014, it was acquired by venture capitalists Greybull Partners from the original owners, Switzerland’s Mantegazza family. Greybull is now reported to be considering its next move with the carrier.

EasyJet has generally grown without purchasing rivals, but a major move in 2007 saw it buy GB Airways, the former British Airways franchise, which was a step change for easyJet at Gatwick. It also bought Flybe’s Gatwick slots in 2013, paying £20 million.

Monarch has however also recently said it was looking at opportunities itself, fuelling counter-rumours that a merger with a rival may be on the cards.

Deutsche Bank has been appointed to advise on Monarch’s future direction and one scenario being put forward would be for Monarch and a charter brand such as Thomas Cook Airlines to combine under a new holding company. Another is for Monarch to become part of a foreign low-cost carrier.

A deal with Jet2 parent company The Dart Group could also see the northern carrier come south for the first time, while another scenario is for Monarch to become part of a foreign low-cost carrier.

Neither airline was available to comment.