Keir Starmer's former aide grilled

The hearing is expected to focus on McSweeney's role in the decision-making process and whether No 10 pressured civil servants to grant security clearance.

Starmer has denied any wrongdoing, but the scandal has continued to dog his administration.

The prime minister's former spin doctor, Lord Matthew Doyle, is also expected to give evidence.

The inquiry comes as the Labour Party faces increasing pressure to demonstrate greater transparency and accountability in its senior appointments.