Hill also defended his decision to step down in the wake of the 23 June referendum which saw the UK vote to leave the EU.
He told members of the European Parliament's Economic and Monetary Affairs (ECON) committee that it was “the right thing to do” following the victory for the Leave side.
Hill also appeared to rule out a second referendum, saying that the “wishes of the public had to be respected.”
This Friday, Hill, the commissioner for financial stability, financial services and capital markets union, will shut the door on his top-floor office in the European commission’s Brussels HQ for the last time and return to the House of Lords after the summer holidays.
His return to the UK comes as British MEPs find themselves under pressure to cede influential positions they presently hold within the assembly.
Julian King currently the UK’s ambassador to France, was nominated by ex-UK prime minister David Cameron to replace Hill. King is likely to get the nod of approval from Jean-Claude Juncker, the president of the European commission, by the end of this month.
King will also have to be approved by member states and will face questions from MEPs but that hearing is unlikely to happen until the autumn.
In his final appearance before the ECON committee, Hill spoke of his support for building a Capital Markets Union (CMU) and the measures his commission colleague, Valdis Dombrovskis, who will take up Hill’s dossier, is likely to take forward.
He told the committee, “I know some people have been wondering whether my leaving will mean a change of direction for CMU. I have seen theories about it being significant that Valdis, with his responsibilities for the euro, is taking over. Can we expect to see a new emphasis on institutional change? Will we get a Single European Supervisor? Will Britain leaving the EU mean that CMU will become more "ambitious"?
“Does it mean that the brake will come off, as some have suggested? Or does it mean the brake will go on?
“To all of those people, and all of the theories, I would say that the whole point about the way we have built the CMU is that it reflects what people – member states, the industry, Parliament and others – told us they wanted.
“There was no appetite among member states for a single European supervisor. But there was complete agreement that this is a single market project for all member states. The analysis of why we need it has not been changed by the UK's vote to leave the EU. Or if it has, it has been to strengthen the case.”
Hill added, “The global outlook is more uncertain than when we began thinking about the CMU because of slowing growth in emerging markets and the uncertainty about the UK's future relationship with the rest of the EU. So the focus on growth and on increasing financing to the wider economy is more urgent than ever.”
He said “the lesson the financial crisis taught us about what happens if you put all your eggs in one basket and suddenly bank liquidity dries up is still valid.”
He went on, “It's absolutely essential for the EU to continue diversifying the funding sources for its economy, particularly with London outside the EU. Europe needs to develop the shock absorber function that capital markets provided after the crisis in America, and which allowed the US economy to bounce back quicker.
“What has changed is that without the UK the CMU might take longer to build, but to my mind that makes the need to make progress all the more urgent. And, also of course the big known unknown is the nature of the relationship the UK will have with the EU once it has left.”
“Building a CMU was never going to be easy. I was never under any illusions about that. But today, my message to people would be to stick with it, to keep hammering away at the barriers to free movement of capital for the years ahead. I'd urge Valdis Dombrovskis and colleagues in the European Parliament to do that because, with or without the UK on board, it's the right thing to do. I think we've laid the foundations with an ambitious agenda.”
Hill said, “As the holiday season is upon us, I do hope that Valdis will share my frustration at the car hire market and take forward ideas to make prices more transparent. The plan is still for the Commission to come forward with follow up actions on how we can deepen the single market for retail financial services this autumn.”
Assessing his short time in office, he concluded, “Step by step, I feel we've put in place a range of measures to strengthen trust in the financial system, increase competition and choice. This is work that can support the growth and investment we need to create jobs in Europe.”
Several MEPs praised Hill, including Burkhard Balz, a German EPP deputy, who said his return to the UK would be a “big loss” while French Socialist Pervenche Beres admitted that while it was “surprising” a commissioner from a non-eurozone country had got the financial services dossier, Hill had been a “key player” in creating the CMU.
French ALDE deputy Sylvie Goulard reminded Hill that she was instrumental in him having to face a second nomination hearing.
The Conservative peer was recalled for a second public grilling after failing to impress the European Parliament with his grasp of the brief – an unprecedented move by MEPs that raised alarm in London.
She said, “Yes, I insisted on a second hearing but you have given a good impression for the UK and I would’ve preferred you to stay on. I hope you can now tell London that the EU wants to maintain constructive cooperation with the UK.”