Tesco multichannel director Robin Terrell has stepped in to run the flagship UK business as an investigation begins into a profits overstatement.

Tesco chief executive Dave Lewis would not confirm that UK boss Chris Bush is one of four people who have stepped aside in order to facilitate the inquiry, but said Terrell is “now running and leading the UK leadership team”.

The other three people to have been suspended are thought to be UK finance director Carl Rogberg, UK food commercial director John Scouler, and food sourcing director Matt Simister. It is also understood clothing boss Jason Tarry has taken over Scouler’s responsibilities.

Tesco shocked the City this morning with the announcement of an investigation into its half year profits accounting.

Lewis said the issues revolves around Tesco’s “commercial income” - the transactions between Tesco and its suppliers. An employee brought the issue to the attention of Lewis on Friday.

He said the investigation centres around the timing of payments, and added: “It seems to be related to the first half of the year, but if the investigation extends to other years then we will follow it there.” Lewis said the investigation will look into whether revenue due from suppliers was reported in the wrong time period.

Tesco chairman Richard Broadbent defended his position and said that this issue is “out of the ordinary” and is being dealt with immediately. He said: “If you go back over the last 18 months, we have dealt with so many issues, we’ve taken decisions when we were not making progress, and ultimately we changed the management. We have not ducked any issues.”

Broadbent said that while Tesco is currently in transition from former finance director Laurie McIlwee to new finance chief Alan Stewart, who does not start until December 1, “the finance position has been covered at all times”.

He added: “Tesco is an important company in the UK and it deserves to be taken to better times.”

Broadbent said: “Shareholders will decide if I am part of the solution or the problem.”

Lewis said the investigation will be “full and deep” and “will include anybody with a point of view or insight into the situation”, indicating former chief executive Philip Clarke may be contacted.

Tesco’s interim results will now be announced on October 23 instead of October 1, and Lewis said he will provide an update on the investigation then.