The Duke of Cambridge should have gone further in his comments condemning slavery during a Caribbean tour, Labour leader Sir Keir Starmer said.

William faced calls to issue a public apology for slavery during the tour, which was marked by a series of controversies around the UK’s colonial past.

The duke denounced slavery as “abhorrent” and said “it should never have happened” but Sir Keir suggested he could have said more – and may do so in future.

William “could have gone further”, Sir Keir said, but he acknowledged “it’s a difficult one”.

“I think that he may go further in the future.”

William and Kate faced criticism during their eight-day tour, from accusations Belize locals were not consulted about a royal engagement to calls for slavery reparations from the monarchy in Jamaica.

Sir Keir acknowledged the duke and duchess were trying to communicate a difficult message at a time when links to the monarchy are being reconsidered in the three countries – Belize, the Bahamas and Jamaica – visited on the tour.

“William and Kate went on an important trip with important messages, including messages about the changing nature of the Commonwealth going forwards, and that is difficult.”

The Labour leader said it was important for the Commonwealth to modernise to strengthen the bonds with the UK.

But he was it was a “bit odd” for the Duke and Duchess of Cambridge to ride in the back of the same Land Rover that the Queen and Duke of Edinburgh used 60 years ago.

“In a sense, what William and Kate were doing – which I applaud – is saying: ‘We’re looking to the future’, but that all harked of the past, so I didn’t quite see how that actually fit that well with the aim of their trip.”