The sale of Royal Mail’s parent company to a Czech billionaire has been cleared by shareholders.

The approval of the £3.6bn deal, first proposed a year ago, will see the 500-year institution taken over by Daniel Kretinsky’s EP Group.

Just over 80% of the shareholders of International Distribution Services (IDS), Royal Mail’s owner, voted in favour of the takeover on Wednesday afternoon.

Mr Kretinksy said he will put “employees and customers at the heart of everything IDS does”.

Under the terms of the deal, the EP Group will have to maintain the one-price-goes-anywhere Universal Service Obligation (USO).

This obligation currently means it has to deliver letters six days per week, Monday to Saturday, and parcels Monday to Friday.

The company has committed to maintaining the USO for as long as it owns Royal Mail. Last year, Mr Kretinsky told the BBC he would honour the service – in whatever form it takes – “for as long as I am alive”.

Keith Williams, chair of IDS, said Mr Kretinksy’s commitments in the deal “provide our customers, colleagues, and broader stakeholders with safeguards for the provision of the USO”.

A review of the USO closed earlier this month, with Royal Mail suggesting to the regulator Ofcom that reducing second class deliveries to every other weekday would save up to £300m a year and give the business “a fighting chance”.

However, the Greeting Card Association said on Wednesday it was “deeply concerned” about the Royal Mail’s proposal.

“If proposed changes to the USO are implemented later this year, the small businesses we represent will be left increasingly reliant on an uncapped, unregulated first-class postal service that will put significant pressure on them, and the consumers they serve,” the group said.

Mr Kretinsky has a net worth of £6 billion, according to the 2024 Sunday Times Rich List.

In addition to owning 27% of West Ham United football club and 10% of Sainsbury’s, Mr Kretinsky’s companies also own a gas transmission service which still pipes Russian gas to Europe, albeit reduced levels, paid for and with the consent from the European Union.