A Ryanair passenger says she was fined £75 because the wheels on her suitcase were poking out of the airline's bag sizer - even after she paid extra to take it on board. Gilly Bachelor was flying from Birmingham Airport to Malaga in Spain when she was stopped at the boarding gate.

The 55-year-old said she was told she couldn't bring the bag on board despite paying extra for both the priority and two cabin bags options. Gilly alleges she was fined an extra £75 by Ryanair to take the bag on board, on top of the £125 flight, during the "stressful" episode.

"I've taken that bag on lots of flights with no problem, just not Ryanair," the passenger from Brewood, Staffordshire, told Luxury Travel Daily.

"As we were boarding, a gentleman was checking all the bags. They put it in the sizer and the issue was with the wheels and that it was slightly too wide. I travel a lot myself, so I'm usually pretty relaxed, and clearly this caught me out this time."

Gilly, who is a travel agency owner, claims a member of staff was checking every bag as passengers boarded the aircraft, with at least 20 pulled aside and fined.

She claimed: "Ryanair is a very low cost airline, so they operate to tight margins and will generate extra revenue wherever they can. I also heard that Ryanair staff receive an incentive for every bag they flag as oversized.

"I checked and it's true, but it's only a small portion of the fine. Even so, it's clearly enough to keep staff vigilant and enforce the rules strictly. At least 20 people were caught out."

Ryanair's boss announced last year that it would increase incentives paid to airport staff from €1.50 to €2.50 for every non-compliant carry-on bag they take from passengers. Michael O'Leary, the chief executive of Ryanair, said at the time: "I make absolutely no apology for it whatsoever."

Gilly added: "Ryanair gets a lot of criticism, but the rules are clear and easy to follow. I used them outbound because the timing worked, but flew home with easyJet and my bag was fully compliant, as it would have been with Jet2.

"My advice is to check the size rules carefully and invest in a compliant bag. It's much less stressful than being caught at the gate and paying a fine."

A Ryanair spokesperson said: "This passenger booked a Regular Fare ticket for this flight from Birmingham to Malaga (27 Nov), which allowed them to carry a small personal bag and 10kg cabin bag onboard.

"As this passenger's bag exceeded the permitted size, they were correctly required to pay a standard gate baggage fee ( £75) by the gate agent at Birmingham Airport."