An activist has taken measures into her own hands after Transport for London (TfL) bosses banned adverts in support of farmers on the London Underground as they deemed them “too political”.

TfL and London Mayor Sadiq Khan have been criticised for perceived double standards after adverts in support of assisted dying were allowed to be put up across the network in the lead up to a vote on the matter in the House of Commons.

The National Farmers Union (NFU) had been due to spend £40,000 on posters around Westminster station with a “Stop The Family Farm Tax” campaign to hopefully keep the issue in the minds of MPs when they return to Parliament on January 6.

But Transport for London (TfL), who report to Labour London Mayor Sadiq Khan, have banned the ads.

The unnamed activist accused Khan of “trying to silence the farmers” as she took to placing homemade posters in stations and on trains herself.

In a video she said: “We disagree with you Sadiq, we think this is a really important subject and we believe that the people have the right to know.”

The government has come under pressure since announcing in the October budget that farmers exemption from paying inheritance tax on their estate would be stopped for properties valued at more than £3 million.

In November, thousands of farmers took to Westminster to call for the government to reverse the decision which the NFU claims will lead to family farms being sold off to large corporations due to their inability to pay the tax.

The activist added: “Apparently, the inheritance tax which our farmers are facing is ‘too political’ but it affects everybody, absolutely everyone. No farmers, no food.

“According to Mr Khan, these are far too political but not as political as the assisted dying bill which were allowed to be used throughout the underground.”

Victoria Atkins, Tory rural affairs spokesman, told the Mail “Labour know they’re in the wrong” and that they were “trying to silence those who are pointing this out to their MPs”.

She said: ‘It may be news to the Labour mayor, but Londoners and commuters eat food. They will be hit by higher food prices and weakened food security once Labour’s Family Farm Tax and National Insurance hikes take their toll on British farms.”

TfL said the adverts for assisted dying put up by campaign group Dignity in Dying were compliant with its advertising policy but that it had not allowed the NFU adverts because they “contains imagery and illustrations which are politically controversial” and “promotes a party political cause or electioneering”.

A spokesman for the NFU said: “We were surprised and disappointed that TfL refused to allow us to advertise this campaign on behalf of Britain’s farmers, especially given all the campaigns from other groups they have allowed.

“It makes no sense, even within their own rules.”