The UK will sanction individuals believed to be involved in Chinese government-backed interference in Britain’s democratic process, amid reports that millions of voters had their personal information hacked.

Ministers will release details on Monday about a cyber attack on the Electoral Commission and 43 people, including MPs and peers.

Steps to increase pressure on Beijing include considering sanctions against individuals believed to be linked to the alleged activities, according to multiple reports.

Deputy Prime Minister Oliver Dowden is expected to tell parliament that Beijing was behind a wave of cyberattacks targeting MPs and peers and gained access to the personal details of 40 million voters through a hack of the election watchdog.

A small group of politicians who are hard-line on China are said to have been summoned by parliamentary security director Alison Giles to attend a briefing about the event.

They include former Conservative leader Sir Iain Duncan Smith, former minister Tim Loughton, crossbench peer Lord Alton and Scottish National Party MP Stuart Macdonald, the Sunday Times reported.

The four are members of the Inter-Parliamentary Alliance on China (IPAC) pressure group, which focuses on issues involving the increasingly assertive Asian power.

It is understood some of those affected are preparing to publicly address the matter together on Monday.

A government spokesman declined to comment on Sunday.

Meanwhile, reforms to the UK’s Espionage Act continue to make their way through Parliament, with the Investigatory Powers (Amendment) Bill also introduced in the House of Commons on Monday.

The legislation includes measures to make it easier for agencies to inspect and retain large data sets, such as publicly available online phone records.