The elections watchdog is examining Labour’s spending on Angela Rayner’s general election battle bus following Conservative complaints.

The Tories claim 24 Labour MPs may have broken the law by not declaring a visit from the battle bus in their election expenses.

They are calling on the Electoral Commission to launch a full inquiry into what they say is an abuse of the system to gain an unfair advantage.

A Labour spokesperson said: “All necessary declarations have been made in line with the rules, including with regards to the ‘Change’ battle bus.”

Labour’s deputy leader criss-crossed the country in the ‘Change’ bus to drum up votes in the run up to 4 July’s general election. Other leading Labour figures, including Lisa Nandy and Anneliese Dodds, also used the bus.

Under electoral law, candidates are meant to declare such visits in their expenses as a “benefit in kind” if the visits promote their own election campaign.

If the visit was to promote the national party’s campaign then it is meant to be declared to the Electoral Commission.

The Conservative Party claims in a letter to the Commission that each battle bus visit “effectively became a ‘rally’ and press conference for the individual candidate” and was used to promote the candidate on social media.

According to Tory analysis of social media posts and official spending returns by candidates, 24 Labour MPs did not declare a visit from the battle bus and others did not follow the rules in different ways.

Shadow local government secretary Kevin Holinrake said: “In tight races across the country, Labour MPs have benefitted from Labour’s battle bus without declaring it.

“Cabinet ministers are involved, who must know better.”

He is calling on the Electoral Commission to “undertake a forensic investigation working alongside the police”.

Labour insists all the necessary declarations have been made.

The Electoral Commission says campaign spending by individual candidates does not fall under its remit and is a matter for the police.

But it say it is examining national spending returns submitted to it by the Labour Party, something it does have jurisdiction over.

A spokesman for the watchdog said: “The classification of spend on a battle bus will depend on whether the spending promotes the party or the candidate. 

“Activity promoting a candidate is typically reported on the candidate return, activity promoting the party must be included in the party return.

“The Commission is considering information relating to the Labour Party’s use of its battle bus in line with the Commission’s Enforcement Policy.”