Private equity firm Castlelake is calling on investors in Easyjet to lobby the budget airline to accept its third takeover offer, after the FTSE 250 carrier slapped down its latest bid over the weekend.

The bidder said on Monday that Easyjet has rejected three successive takeover bids and criticised the airline for its “unwillingness to engage meaningfully”. 

Castlelake said its most recent approach was made on Saturday and included an offer price of £6.25 per share, valuing the firm at £4.7bn, well above Easyjet’s £5.17 share value. This followed previous offers of £5.60 and £6 per share.

Following the rejection of its latest bid, the private equity firm has gone public to encourage Easyjet shareholders to consider this proposal and “provide their views” to the airline directly. 

Castlelake claims that its latest offer “substantially de-risks the execution of the Company’s business plan”. 

But Easyjet hit out at the US firm’s approach on Monday, confirming that it rejected the third bid, which it said fails to reflect the airline’s “position of strength”.

The airline’s board accused Castlelake of attempting to acquire it “on the cheap”.

The private equity firm’s latest offer comprises a 59 per cent premium on Easyjet’s share price on the date when Castlelake tabled its first bid, and a 71 per cent premium on the airline’s interim trading update in April.

At this update, the airline revealed that it is forecasting a pre-tax loss of between £540m and £560m as the Middle East conflict closed travel routes and sparked fears of a jet fuel shortage.

Announcing these results, Kenton Jarvis, Easyjet chief executive, said: “Our first half financial performance worsened year on year, impacted by the conflict in the Middle East and the competitive environment in some markets. 

“Following our busiest Easter holiday period ever, the operational ramp up into peak summer continues as planned.”

Castlelake is urging investors to share their views on this proposal before 5pm on 26 June, when the bidder is required either to make a formal offer or to walk away.

Earlier this month, the budget carrier hit out at Castlelake’s “highly opportunistic timing,” claiming its prospective owner was pouncing on its low share price, slumped amid the travel chaos caused by the Iran war.

Easyjet’s share value is “temporarily depressed due to the current situation in the Middle East and its impact on customer confidence and jet fuel prices,” the firm said.

The airline’s shares had fallen by some 20 per cent since the start of the year to 396p, but have since recovered much of their value and are now steady in the year so far, climbing three per cent to 517p on Monday.