It's the dark cloud that has been hanging over the BBC's much-loved Strictly Come Dancing for more than six months.

But now the investigation that began with accusations against the show's professional dancer Giovanni Pernice has widened after more complaints surrounding the hit show.

It has heaped further turmoil on Strictly, which is deemed to be the jewel in the Corporation's crown and is still watched by more than ten million people.

Sources have told the Mail that the accusations have prompted bosses to extend the inquiry to look at other matters, and individuals, involved with the dance series as they prepare for its 20th anniversary.

It means that Mr Pernice, who has already let his frustrations at the investigation be known, faces an even longer wait for an outcome after three former dance partners, including actress Amanda Abbington, instructed lawyers to make 'serious complaints' about his conduct.

It also threatens to damage Strictly, the BBC's biggest Saturday night success story since The Generation Game.

A television source told the Mail: 'This investigation is no longer just solely about Giovanni but other, more wider issues. The show has been going for 20 years and the whole veneer of Strictly is so sparkly and lovely, of course there will always be people who feel hard done by.

'Amanda's complaints have started something massive, it has opened the door for others to come forward about things they haven't been happy with.

'It is all a big headache for the BBC, it is about to celebrate a massive milestone with its 20th anniversary.

'Having the Giovanni complaint has been a big enough issue, but now it looks like there is more to be scrutinised and looked into.'

Sources close to Mr Pernice say that he fully expects to be exonerated.

Insiders say also that the widened inquiry will now present the 33-year-old as possibly being a 'small fish' in Strictly's potential downfall.

He quit the show after nine years following claims by Ms Abbington, star of Sherlock and Mr Selfridge, that he bullied her in training, claims which he denies.

In May it was revealed that the 50-year-old Ms Abbington had instructed London law firm Carter Ruck to represent her against the BBC.

The BBC last night refused to comment on the matter but it did confirm in a statement that more than one complaint has been made. It was revealed last week that a plea was made online for anyone involved in the show at any time in the past two decades to come forward and speak to the BBC if they had experienced any bad behaviour.

Writing in The TV Mindset, a social media forum for TV industry workers, an anonymous member insisted: 'It is important to hear as many accounts as possible from others who were treated inappropriately, had grievances, or potentially identify others that were.

'This is crucial in supporting Amanda's case, as well as potentially anyone else's. It is also ultimately to support all freelancers and the industry as a whole by standing up to such practices.'

The chaos now surrounding the show was said to be typified by the surprise announcement on Monday that former fan favourite the dancer Aljaz Skorjanec would be returning show after a two-year absence.

It comes a month after the full line up of professional dancers for the next series was announced by the Corporation.

Some within the show have questioned why he was not unveiled alongside with the other professionals – particularly because the Beeb left fans waiting for some weeks following Mr Pernice's departure before putting the final list out.

Insiders also noted that the Press were not given a heads up – instead, the announcement was made on the BBC's own magazine programme, The One Show, on Monday evening.

One source said: 'Usually when something like this happens the BBC give the wider media a heads up but this time the first anyone knew of it was a chat with Aljaz on The One Show and then it was quietly put up on the BBC's press centre at 7.30pm the same day.

'It meant that the announcement was in keeping with the narrative the BBC wanted, no questions were asked as to why he was being unveiled now.'

A BBC spokesman said of the widened investigation last night: 'We recently issued a statement urging the media not to indulge in speculation about complaints related to a high profile show and that position remains the same.'