Northampton North MP Michael Ellis says the Tory battle bus did not break election rules by declaring a visit to his constituency as part of its national campaign.
A furore erupted in February, when it emerged Conservative headquarters did not declare thousands of pounds in hotel bills occupied by activists on its battle bus during the 2015 election.
“A van with three or four people in it is not the same as a battle bus loaded with activists from here there and everywhere.”Labour candidate, Sally Keeble.
But it sparked a further debate as to whether the Tory national party “bankrolled” candidates in marginal seats.
A Channel Four investigation found that activists were briefed on local issues, claiming that in Northampton North the team was given advice on the “new bus station, shops in the town centre and pedestrianised shopping areas”.
Critics have claimed individual candidates should have been made to declare the battle bus visits under their own expenses, which are capped at between £12,000 and £15,000 for the 39 days before an election.
However, Northampton North MP Michael Ellis believes the national party was right to declare the bus as part of its national campaign.
He said: “All the political parties have always used battle buses as part of the national campaign.
“There is nothing new about that it has been going about for decades.
“I think the Labour party had a pink bus come to Northampton, totally routine and declared nationally.
“The Electoral Commission has acknowledged that battle buses are part of the national campaign.”
However, the commission is currently investigating the Conservative “return” for the 2015 elections, and is looking into around £100,000 of undeclared hotel bills related to the battle bus.
Tory headquarters has said an “administrative error” was to blame.
But an Electoral Commission spokesman also said the election watchdog “would consider any information that was reported by Channel Four”.
“It is a live investigation, so we will not be making further comment until the investigation concludes,” he added.
Labour’s Northampton North candidate, Sally Keeble, who lost by around 3,000 votes to Mr Ellis in 2015, did receive a constituency visit by Labour’s infamous pink “woman to woman” van in the election run-up.
But she claimed the pink bus was “an entirely different type of operation” to the Conservative battle bus.
She said: “It came purely to encourage discussions around women’s issues.
“A van with three or four people in it is not the same as a battle bus loaded with activists from here there and everywhere.”