IAN Blackford has accused Theresa May of being a “liar” during a fiery debate in the House of Commons.

During his speech, the SNP’s leader at Westminster asked the Prime Minister is she had carried out an economic assessment of the impact her deal would have on the UK economy.

READ MORE: Ian Blackford brands Theresa May a 'liar' in heated Commons exchange

May, in her response, claimed that an economic analysis has been carried out which led to someone from the SNP benches shouting appearing to shout “That’s not true”.

After May resumed, something was shouted at her again, with the Tory benches accusing someone on the SNP frontbench of calling the PM a liar.

WATCH: Ian Blackford accuses Theresa May of 'rewriting history'

After an intervention from the Speaker of the House, in which he sought advice as to who said what, he demanded a retraction from Blackford, who obliged “out of respect” for the Speaker.

Watch the clip below: