This week has seen top City boys queuing up, two-by-two, as the Parliamentary Commission on Banking Standards (PCBS) called them in for a grilling on UK banking standards, rate-rigging scandals and big fat cheques.

In the firing line this morning was Anthony Jenkins and Sir David Walker, Barclay’s group chief executive and chairman, after Lloyds’ on Monday.

During an intense three-hour inquiry, Jenkins told the committee he was “shredding” the legacy left by his former boss Bob Diamond, after (quite publicly) rebuffing a £2.75m bonus having decided it would be “wrong” to receive a cheque too fully-loaded.

It is still far too early to see whether there has been any material change in Barclays’ culture. Rome wasn’t built, or-re-built in a day, and the jury will still be left with a few big questions over the British bank’s cultural DNA after today’s session.

Diamond on his part had received a £2.7m annual bonus for 2011, a pay check of £17m (with the bank paying also his £5.7 tax bill) after resigning amid the interest rate rigging scandal.

The boss was known to lead an "aggressive" and "self-serving" culture in the bank, the committee heard, while hush-hush talks in the City from former Barclays’ people push it a bit further, describing it as “rotten”.

The multimillion-bounty led to the forced resignation of Alison Carnwath, former chairman of the Barclays remuneration committee, who claimed to have been the lone voice for Diamond receiving "zero" bonus.

Along with Walker, Jenkins announced, avoided –and confessed- a few things.

The Committee jumped at the chance to enquire about The Bonus, remuneration and more specifically Sir John Sunderland, the man in control of it –he who replaces Mrs Carnwath.

“The problem we have with [Sunderland’s] evidence is that he didn’t think he had made a mistake (in regards to Bob Diamond's pay off), even in retrospect?” the committee asked.

“You'll have to trust my judgement,” replied Walker, in what looked more and more like a battledome.

Walker and Jenkins informed the MPs of a bonus slim down at Barclays following yet another £1bn provision to cover compensation for interest rate swap products and mis-selling of payment protection insurance (PPI).

According to Barclays, the scandal-hit year is now costing the bank around £2.6bn in compensation: PPI damages will go to borrowers who were (mis-)sold loan insurances (to protect them if they missed repayments due to illness or redundancy), but were not actually eligible to claim it.

During the tense discussion, Jenkins let out that he would step down if there was a regulatory failing under his watch.

This comment seemed too trouble-free for the Committee not to pick upon: Jenkins was head of Barclaycard from 2006, and throughout the time PPI products were sold.

“We worked hard to modify PPI products and we didn't get it right completely” was what Jenkins had to answer. He added: “it's a question of proportionality.”

This answer baffled the Committee; but not as much as when he spoke about the LIBOR-fixing –which cost the bank $450m in fines. “I first learnt about Libor on the day the Libor fine was announced,” he said.

When the committee asked him if he questioned the banking culture while working closely with Diamond, Jenkins took the time before calmly answering, “Yes.”

What he meant by this assent, was that he had been arguing “for a change in culture since 2012.”

Rumours were sparked by Committee chairman Andrew Tyrie when he said it was possible the Barclays bosses would be called in before the Committee again.

But next in line for the grilling are JP Morgan and HSBC’s heads, who will give the Committee more to query until their new report is published.