Rob Howley's rugby career is in ruins after he was sent home from the World Cup in Japan due to a potential breach of betting rules.

The 48-year-old former Wales captain and scrum-half flew home as Wales' World Cup squad continued preparations for their opening game against Georgia next Monday.

And as Howley made a rapid exit, it brought a full stop of startling proportions to the Wales assistant coaching role he had held since 2008.

Howley had been one of Wales head coach Warren Gatland's most trusted lieutenants, with the pair having worked together as coach and player at Wasps when their time was highlighted by a Heineken Cup triumph in 2004.

That connection continued early in 2008 when one of Gatland's first appointments to his Wales staff was a player who performed with distinction on 59 occasions for his country, captaining them 22 times.

And when Gatland spent time preparing for heading up the 2013 and 2017 British and Irish Lions tours, Howley stepped in as interim Wales boss, masterminding a 2013 Six Nations title triumph.

But that proud reputation has now been permanently tarnished amid developments that will send shock waves reverberating around the rugby world.

And it could not have come at a worse time for Wales – right at the start of a World Cup campaign they are widely expected to perform well in.

Howley took a full part in Monday's opening training session that was watched by 15,000 people at Kitakyushu Stadium.

But it is understood that matters escalated quickly following that public work-out, and he subsequently left the camp.

As a player, Howley was among the finest Wales performers of his generation, leading from the front and at times propping up teams that consistently struggled.

And he moved seamlessly into coaching, transferring his playing knowledge to a tracksuited role and establishing himself as a key figure within the Wales set-up.

But it has all ended in the most unceremonious fashion, raising huge questions about whether he will even work in rugby again.

Wales – and Gatland in particular – are left to clear up the mess left behind, although the New Zealander's resolve, and that of his players and staff, is unlikely to be affected.

Howley, though, could hardly have made life more difficult.