The West Lancashire MP is currently receiving oral chemotherapy treatment for metastatic breast cancer.

Dalton introduced the cancer plan to parliament last month and led the HIV Action Plan and Men's Health Strategy.

In a letter to Prime Minister Keir Starmer, Dalton said she was stepping back from ministerial duties to manage her condition and focus on representing her constituents.

She added: ‘My constituents deserve a member of parliament to represent them with diligence and conviction.

‘Whilst my oral chemotherapy treatment will not stop me from being that champion for West Lancashire, I believe now is the right time to take the reasonable adjustments I need to both manage my condition and focus on being a constituency MP by stepping back from ministerial duties'.

In response, health secretary Wes Streeting said she 'has achieved more as a minister than many politicians achieve in their entire careers'.

Starmer said: ‘You are an exemplary minister and should be extremely proud of the impact that you have made on behalf of this Labour government.'