Labour MPs have privately raised alarm at the number of sponsored corporate receptions for backbenchers that have been arranged by the party, amid concerns about perceived conflicts of interest.MPs have received invitations for networking receptions that include explicit advertisements for property developers or public affairs firms.The invitations are sent to MPs directly from the parliamentary Labour party (PLP) office and forwarded by party whips.“The PLP office has literally become a public affairs agency,” one MP said.“The wording is genuinely shocking.

”An invitation for a summer reception in London said it would be an MP-only event and an “opportunity for members of the PLP and frontbenchers to relax in a private setting with senior party figures as we return from the summer recess”.The PLP reception would be hosted in partnership with the property developer Vistry, the invitation said, and it included a lengthy advertising pitch for the company.“As the country’s largest homebuilder, we leverage our expertise, skills and scale to deliver quality new housing,” it read, going on to promote Vistry’s timber-manufacturing capability.A party source said attendance was optional but at least one invitation made it clear there was an expectation to attend.“These bi-annual events are important for the party, so your attendance would be greatly appreciated,” one said.

MPs are understood to have complained about the explicit corporate nature of the event on an MPs WhatsApp group.A similar event hosted for Labour MPs in the north-west has been sponsored by Mitie, the facilities management company that provides outsourcing services.One MP said this was directly at odds with Labour’s stated values to return to insourcing services.This week MPs were invited to attend a “kickstart economic growth PLP reception” with “important speakers” at Mastercard’s headquarters that had been arranged so MPs would have time to return to vote in the Commons.“PLP staff are on hand outside and in the venue,” the invitation read.

The credit card company also hosted a reception for Labour MPs in the north-west, with the PLP office invitation offering a tour of Mastercard’s “experience centre”, where the company would demonstrate “some of the cutting-edge technology and innovation that’s supporting small businesses”.MPs have previously complained about a winter reception, held for the London regional group of MPs, being sponsored by the communications consultancy Kanda.The invitation included a lengthy advertising blurb for Kanda, which said the company worked with clients “to understand, navigate and respond to the commercial drivers impacting the real-estate sector, including government legislature [and] local issues”.Sign up to Headlines UKGet the day’s headlines and highlights emailed direct to you every morningafter newsletter promotionFirst Rail, a leading transport group operating Avanti West Coast and Great Western Railway, sponsored a similar reception for the northern regional group of MPs and another event with Go Ahead, also a large public transport group with contracts across the north of England.A regional reception in December for Scottish MPs was sponsored by Octopus Energy, at the same time the renewable energy group was pushing for a zonal pricing scheme that would benefit Scotland.

The energy secretary, Ed Miliband, has since decided not to go ahead with the project.Members of the PLP group of MPs from the north of England said they were frequently invited to commercial briefings, including with BP Teesside, Yorkshire Water and the British Association of Independent Exploration Companies that lobbies on behalf of the North Sea energy industry.The invitations were also promoted to MPs by party officials.A Labour party spokesperson said: “Commercial partnerships at events are a longstanding practice and have no bearing on party or government policy.”