Tory MP Andrea Jenkyns has quit as a ministerial aide to fight for leaving the customs union via her membership of a powerful Commons committee.

The Morley and Outwood MP resigned from her role as parliamentary private secretary (PPS) at the Ministry of Housing, Communities and Local Government, on Thursday, saying she wanted to focus on securing the “right kind” of Brexit.  

Jenkyns is a member of the influential Brexit Select Committee, led by Labour MP Hilary Benn, but says it is “unbalanced” in favour of Remain supporters.

The MP, who defeated Labour’s Ed Balls to win her seat in 2015, said it had been a “huge honour” to serve as PPS but had decided to stand down to “concentrate more of my time on obtaining the right Brexit for our country and my constituents”.

Although unpaid, PPS roles are often seen as the first rung on the ladder for ambitious MPs vying for ministerial positions.

Jenkyns said: “Standing down as a PPS was a difficult decision for me, but I have decided that this is something that I need to do to be able to fully commit to my other parliamentary duties.

“I have an obligation to my constituents and the 17.4 million people around the country that decided to leave and take back control of our destiny.

She said Theresa May had her “full support” but in a pointed message about the kind of Brexit deal she wants, Ms Jenkyns said: “We want to see a new relationship with Europe, with a new model not enjoyed by other countries – nothing that leaves us half-in, half-out.

“And in order to achieve this, we need to leave the customs union.”

Explaining her concerns about the Exiting the European Union select committee, she said: “Currently, there are 21 members on the Brexit committee, only seven of which voted to leave the EU.

“It is my opinion that the reports produced by the committee have been unbalanced in favour of us either remaining in the EU, the customs union or delaying our departure.

“I, therefore, feel I need to spend more of my time doing all I can do to correct this imbalance and be a robust voice for the benefits of Brexit.

“During my time on the committee, it has become clear that some of my colleagues are committed to upsetting the democratic decision of the British people.

“Over the past few months, this situation has caused me much frustration, but since this disparity is unlikely to change I feel it is my duty to give the necessary attention to this vitally important role.”

Her comments came as the committee published a report criticising the Government’s failure to decide on a customs model for the future and suggested that staying in the customs union was the only “viable option” until a replacement was ready.