LONDON, June 29 -- Prince Harry fears King Charles could miss a rare chance to reunite with Prince Archie and Princess Lilibet after uncertainty over security arrangements cast doubt over the Sussex family's planned visit to the UK next month.

According to The Guardian, the Duke and Duchess of Sussex had been preparing to travel to the UK with their two children for events linked to the Invictus Games, which are due to be held in Birmingham in July.

The visit would have marked Archie, seven, and Lilibet, five, returning to the UK for the first time as a family in four years and offered what was expected to be a long-awaited reunion with their grandfather.

However, those plans now appear to be in jeopardy after the government declined H...