Labour’s Shabana Mahmood will vow to “reinstate the rule of law” if the party wins power in her first speech as shadow justice secretary.

Ms Mahmood, a former barrister, is set to launch a wide-ranging attack on the Conservatives’ record on the justice system, including the closure of courts in England and Wales, changes to legal aid and the backlog of criminal cases.

The shadow minister will also accuse successive Conservative lord chancellors of “failing to fulfil their historic duty” to defend the judiciary and the rule of law in a speech to legal professionals in London on Monday.

Today, the law treats rape victims as essentially no different from any other witness, and so fails to protect them at their greatest hour of need

She will highlight the fines issued to both Boris Johnson and Rishi Sunak for breaching Covid rules and criticise comments “disparaging” judges and the courts.

Ms Mahmood is expected to say she will “never allow any government I am part of to ignore the law or blame the judiciary for simply doing their job”.

Her speech comes as Liz Truss, herself a former lord chancellor, called for the Supreme Court to be abolished after it blocked the Government’s Rwanda scheme.

While serving as justice secretary, Ms Truss was criticised for failing to condemn a Daily Mail front page describing judges as “enemies of the people” after they ruled against the Government in a Brexit case.

Ms Mahmood is also expected to focus on Labour’s promise to halve rates of violence against women and girls, promising to provide a free legal advocate for rape victims.

She will say: “Today, the law treats rape victims as essentially no different from any other witness, and so fails to protect them at their greatest hour of need.”

A Conservative Party spokesperson said Labour deputy leader Angela Rayner was the only person “on the front line of British politics who thinks they’re above the law” and accused Sir Keir Starmer of being “too weak to sort it out”.

The spokesperson said: “Meanwhile these promises are just more of the same old Labour Party. While they snipe from the sidelines, the Labour Party have no plan to stop crime.

“It is under Labour Party police and crime commissioners that areas have higher crime. Labour voted against boosts in police funding four years in a row. And it was Keir Starmer and his Labour MPs that campaigned to block the deportation of foreign murderers and criminals.”