In the wake of last month's sex scandals, The Old Vic decided to launch an internal investigation into the actor's time with them as artistic director.

Spacey was with The Old Vic for 11 years, starting off in 2004. And The Old Vic last night offered a public apology to the men effected by Spacey's inappropriate behaviour during his time with them.

The Old Vic last night admitted that their investigation "resulted in 20 personal testimonies shared of alleged inappropriate behaviour carried out by Kevin Spacey during his time as Artistic Director".

The Old Vic chairman, Nick Clarry said: "On behalf of The Old Vic Board of Trustees, to all those people who felt unable to speak up at the time, The Old Vic truly apologises. Inappropriate behaviour by anyone working at The Old Vic is completely unacceptable.

"We will foster a safe and supportive environment without prejudice, harassment or bullying of any sort, at any level. We want anyone who works here to feel confident, valued and proud to be part of The Old Vic family."

Artistic director at The Old Vic, Matthew Warchus had this to say: "I have genuine and deep sympathy for all those who have come forward and said they were hurt in some way by my predecessor's actions.

"Everyone is entitled to work in an environment free from harassment and intimidation.

"The Old Vic is now actively engaged in the process of healing and the process of prevention.

"These allegations have been a shock and a disturbing surprise to many of us.

"It is incorrect, unfair and irresponsible to say that everybody knew. But as a result of the investigation, what we have learnt is how better to call out this behaviour in future."

A statement from The Old Vic theatre reads: "The investigation resulted in 20 personal testimonies shared of alleged inappropriate behaviour carried out by Kevin Spacey during his time as Artistic Director.

"Despite having the appropriate escalation processes in place, it was claimed that those affected felt unable to raise concerns and that Kevin Spacey operated without sufficient accountability.

"This is clearly unacceptable and The Old Vic truly apologises for not creating an environment or culture where people felt able to speak freely.

"'This investigation concluded that there have been 20 personal allegations of incidents relating to The Old Vic ranging from 1995 to 2013, with the majority (all but two) falling before 2009."

It adds: "No legal claims, formal grievances, formal disputes, settlement agreements or payments made or authorised were made at all in relation to Kevin Spacey during his tenure.

'It has also not been possible to verify any of these allegations, and it is important to note that Kevin Spacey has not commented on them.'

"The given testimony shows that in all but one case, those individuals alleging inappropriate behaviour by Kevin Spacey did not come forward at the time or asked that no formal action be taken.

"During his tenure, The Old Vic was in a unique position of having a Hollywood star at the helm around whom existed a cult of personality.

"The investigation found that his stardom and status at The Old Vic may have prevented people, and in particular junior staff or young actors, from feeling that they could speak up or raise a hand for help.

"With the exception of one of the claims, none of the reported incidents were raised formally or informally with management.

"Staff who observed this behaviour claimed they were unclear about how to respond; in some cases they did not consider allegations of misconduct to be serious and, where they clearly did, they said they did not feel confident that The Old Vic would take those allegations seriously given who he was.

"The following factors may have contributed to this escalation problem: star power; lack of clarity of The Old Vic's accepted code of behaviour; confusion regarding the impact of reporting misconduct; career insecurity; tribalism between operational and creative staff during his tenure causing information gaps.

"Calling out this behaviour could have been easier if there had been a non-formal and confidential mechanism in place by which complaints could be raised safely within the organization.'

"For those who were affected during Kevin's tenure, our victim support counselling service will continue to be open 24 hours a day, 365 days a year for the next 12 months.

"We hope this goes some way towards providing a support structure for those affected, together with the knowledge that the testimonies they have shared will help inform the way forward at The Old Vic and in the wider industry."