Labour leadership rivals Angela Eagle and Owen Smith engaged in a spot of "sofa hustings" with Andrew Marr and remained cordial throughout. But both candidates – due to begin official hustings on Monday (18 July) – were given brutal treatments by the BBC inquisitor.

Eagle, who said she would be the best Labour leader because she has working class roots, and she is a woman, was quizzed on her hawkish voting record on Libya and Iraq and why she had voted against the establishment of the Chilcot Enquiry.

The former shadow business secretary struggled to justify supporting the invasion of Iraq, while not supporting the UK taking military action in Libya.

When asked if she would allow a second referendum for Scottish independence, Eagle suggested Scotland would have to accept Brexit, just like other regions of the UK that voted to Remain, such as Liverpool and Cornwall. That provoked the ire of Scottish First Minister Nicola Sturgeon, who appeared later on in the BBC show, who pointed out that Scotland was not merely a region.

Marr's next guest, former shadow work and pensions secretary Owen Smith, was asked whether he would support renewing Trident when the vote is held later this month. When he said he would, Marr asked if he is prepared to order nuclear missiles to be launched and kill millions of people – something Jeremy Corbyn said he would never do. Smith said he would, but only as a last resort.

Marr then asked if Smith would be prepared to increase taxes for the rich. Smith candidly declared that he would, as Labour had been too timid on the subject for too long – an apparent reference to the Blairites from which both he and Eagle are attempting to distance themselves from, without sounding too much like Corbyn.

Smith's Article 50 confusion

Smith was on shakier ground when he was asked if he would trigger Article 50 of the Lisbon Treaty, which would begin the formal extrication of the UK from the European Union. Smith repeatedly said it depended on the terms of exit the EU offered. Marr repeatedly pointed out that the exit terms would not be set when Article 50 was triggered, but would be negotiated afterwards. Smith suggested it was not a binary option. Marr demurred.

Later, after a still cross Sturgeon had suggested Scotland may be able to remain within the EU and the UK, and the recently appointed education secretary Justine Greening explained why a cut in education spending was not necessarily bad for education, Smith and Eagle returned for an encore on Marr's sofa.

Both challengers for the Labour leadership said they agreed on everything, and in particular that Jeremy Corbyn was a bad thing. However, when Marr asked why they were both standing and potentially splitting the anti-Corbyn vote, Smith said this probably was not a good thing after all. Eagle agreed with him there, too, though she probably had a different view on which of the two was best equipped to take the Momentum away from Corbyn.