Virgin Trains confirmed the campaign went out to its “entire database” which could potentially reach most of its 21 million annual passengers. 

Following the trial, the offer, worth in excess of £400 per person, was supposed to be sent to just 70 of Virgin Trains’ loyalty customers. 

Natalie Aitken, traveller manager at Virgin Trains, confirmed the company had already received “several telephone calls” within the first hour of the mistake. 

A follow-up email from Virgin Trains retracted the offer stating: “So sorry, we’ve sent you an email by mistake. The email you have just received about a Virgin Trains event at The Grove was a test email and was not supposed to be sent to any of our customers.

“We realise that we might have got you all excited about the prospect of a day at The Grove, and would like to offer you the chance to win one of three places at this event.”

The apologetic email offered customers the chance to win one of three places to attend the event at The Grove on the 28 May instead.

Virgin Trains told mad.co.uk that it would be seeking legal advice should customers pursue the matter further.

The spokesperson added there is “no way” that the company could honour the offer due to the amount of people involved. 

Aitken said Virgin Trains was now in talks with thetrainline.com about compensation costs. Virgin Trains spent £155,322 on its below-the-line advertising over the past 12 months, according to Nielsen Media Research.

Virgin execs will be reminded that Hoover Airlines was taken to court in 1997 following a misleading deal offering customer’s free flights to America in 1992.

The "free flights fiasco" dogged the company for five years and cost £48 million and resulted in three senior executives being axed.