Royal Mail's owner, International Distributions Services, is prepared to back the £3.5bn takeover if Daniel Křetínský makes a formal offer. This revised offer, involving 360p per share in cash, represents a premium of around 73% to the share price before the original offer was announced.

Křetínský, whose investment company currently holds a 27.6% stake in the firm, has committed to a number of "contractual obligations" given Royal Mail's significant role in Britain's national infrastructure. These include commitments that Royal Mail will maintain its current six-day-a-week delivery of first class letters, respect the rights of employees and the integrity of the Royal Mail brand, and maintain its UK headquarters.

The company's performance has deteriorated in recent years, leading to large financial losses. Letter volumes have halved since 2011, while parcel delivery has become more popular and profitable. In 2013, Royal Mail was privatised in one of Britain's biggest state sell-offs in decades, and its shares were valued at 330p apiece at IPO.

Křetínský has until 29 May to submit an official offer or withdraw from the negotiations. Any deal could trigger government intervention under the National Security and Investment Act, which gives ministers increased powers over critical infrastructure transactions.