An MP is facing calls to refer herself to the ministerial ethics adviser over claims she referenced a "conspiracy theory" in a letter to constituents.

Lewes Conservative MP Maria Caulfield sent a letter to her constituents before the council elections warning that the council wants to “introduce a road toll system called a 15 minute city”.

Lewes District Council have refuted this claim, as any road tolls would be the responsibility of the local highways authority, which is Conservative East Sussex County Council.

Councillor Zoe Nicholson, leader of Lewes District Council, said: “This is simply not true. It's a total invention by the MP. 

"I don't know if she is misinformed or malicious, but I do know she sent her shabby letter to residents and my colleagues and I had to reassure them that it was all false.  

"Residents in Lewes district deserve better.”

James MacCleary, Liberal Democrat parliamentary candidate for Lewes, said: “We are all fed up with the relentless misinformation being spread by Conservative MPs and ministers. Residents should be able to rely on information from their MP being accurate and well informed.

"This letter from Maria Caulfield was not only promoting conspiracy theories but also making false claims about council policies and plans.

"Sadly, I am sure that she will find a reason to point fingers and blame others rather than take responsibility and set the record straight."

In response to conspiracy claims, Maria Caulfield said: "I won’t apologise for sending information out to local residents at the local elections last year showing the consultation Lewes District Council were running on page 45 of their Local Planning Document 'Lewes District Local Plan – Issues and Options consultation'. On this page it specifically outlines plans for 10 – 20 minute neighbourhoods and I shared the experience with residents of where this is already in place in places like Oxford."

The ‘15 minute city’ originated as an urban town planning concept to ensure facilities, homes, shops and jobs were within close reach for residents.

Some criticise it as a freedom-restricting mandate that means residents should not travel 15 minutes.