In June 2016 he was a donor to Conservatives IN, one of the pro-EU groups campaigning ahead of in the UK's referendum on its European membership.
Groes donated £10,000 on 9 June 2016 to Conservatives IN, one of the pro-EU campaign groups that failed to deliver a remain vote in the UK referendum on 23 June 2016.  He has also previously made donations to the Conservative Party.
- BNP Paribas Corporate Finance, Bloomberg, accessed 30 June 2016
- Electoral Commission, Conservatives IN Donations, accessed 30 June 2016
- Mega-rich City bankers stump up cash for David Cameron's General Election campaign, Ben Glaze, 'Mirror', Accessed 1 October 2016