The husband of former Labour MP Gloria De Piero has confirmed his home was searched on Wednesday as part of a police investigation into an alleged Chinese spying ring.

James Robinson, a former aide to the ex-Labour deputy leader Tom Watson, issued a statement confirming the raid on the home he shares with his wife, but said he had not been detained or questioned by police.

He said: “I can confirm that police officers visited my home yesterday with a search warrant. I understand their attendance was part of enquiries into those arrested and questioned over matters allegedly relating to China.”

Robinson, the founder and director of Woburn Partners and a former media correspondent for the Guardian, added: “I would like to make it absolutely clear that I have neither been detained, arrested nor questioned in connection with this, or any other, matter.”

De Piero, the former MP for Ashfield, served in the shadow cabinet under Ed Miliband and Jeremy Corbyn. She left the Commons in 2019 and is now a senior adviser to her husband’s firm. There is no suggestion that De Piero was detained, arrested or questioned by police, and the search is understood to have related to her husband.

Robinson, the fourth person with ties to Labour to be named in connection with the investigation, worked as director of communications for Watson in the late 2010s when Watson was the party’s deputy leader.

Anti-terror police arrested three individuals who previously worked for the Labour party on Wednesday. David Taylor, 39, Matthew Aplin, 43, and Steve Jones, 68, were arrested on suspicion of assisting a foreign intelligence service, contrary to the National Security Act. All three were later released on bail.

Taylor, husband of the Labour MP Joani Reid, was a former special adviser to the Labour peer Peter Hain when he was the secretary of state for Wales. He has since worked as a lobbyist with a company called Earthcott. Earthcott is listed as a supporter of a Labour business group, SME4Labour.

Reid, the MP for East Kilbride and Strathaven, said on Thursday night she would temporarily stand down from the parliamentary Labour party while the inquiry takes place. Taylor has also been suspended from the Labour party pending an investigation.

A spokesperson said: “These are incredibly serious allegations. We cannot comment further while the police investigation is ongoing.”

Aplin previously worked as an adviser to Labour in Wales. Jones was an adviser to the former Welsh first minister Carwyn Jones, and to Hilary Armstrong, the former Labour chief whip.

Police also searched the Cardiff home of a fifth man on Thursday, Martin Shipton, 72, the associate editor at the Nation Cymru website. Shipton said in an article published on the website that the raid took place at 6.20am, describing it as a “kafkaesque nightmare where I was unaware of what was going on”. He has not been arrested.

Shipton added that he gave officers a “voluntary statement” about a trip to Hong Kong he attended alongside Taylor, whom he said he had known for 25 years.