David Tennant has said the second series of Broadchurch was "inevitably" going to be criticised by some, claiming: "I think we're a victim of our success to be honest."

The Scottish actor refused to be drawn on the whodunnit drama's remaining episodes, saying he was a "vault of secrets", adding: "I don't tell anyone anything."

The star's comments come as he was picking up the gong for best actor for his role in the RSC's Richard II at the What's On Stage Awards in central London, where Miss Saigon's blockbuster return to the West End swept the board.

After collecting his award, Tennant said: "It's lovely getting a prize for doing something you would do for free frankly. And I feel very blessed in many ways."

Asked about the less positive reaction to the second series of ITV's Broadchurch, the former Doctor Who star said: "I think we're a victim of our success to be honest. The first series was such an extraordinary thing. This country, we never allow lightning to strike twice in this country...we just don't let that happen.

"So, inevitably there was going to be a certain amount of 'it's not as good as the first time'. I think it is. I think it's a wonderful series that I'm very proud to be part of."

The star, who last week took part in BBC Radio 4's Just a Minute, refused to sum up in one word what he thought viewers would make of the series two finale.

"Not a single adjective, nothing," he said.

Tennant, who stars alongside Olivia Coleman in the drama, hailed his co-star and remained tight-lipped about how he felt about a third series or a spin-off for their characters.

"There's nothing finer than working with Olivia. I'd like to do that everyday of my life, but I think the story will lead that.

"I think what's been wonderful about the second series of Broadchurch is that it's not been the same type of show as the first series and therefore the story has to determine whether there's more to tell," he said.

Long-running hit Silent Witness triumphed in a head-to-head clash of the crime dramas last month as it edged ahead of Broadchurch.

On January 19, the BBC1 forensic pathology programme pulled in an average audience of 5.9 million viewers, while the ITV show managed 5.7 million, which included viewers of its catch-up +1 channel.

Meanwhile, back in the spotlight at the What's On Stage Awards, Miss Saigon won nine awards at the event, hosted by Mel Giedroyc and Steve Furst, at the Prince of Wales Theatre.

Among the gongs it won at the awards, voted for by the theatre-going public, were best actress in a musical for Eva Noblezada, best choreography, best set design and best West End Show.

It also won the best actor in a musical and best supporting actress and actor categories.

The revival of the hit musical, which tells the story of a bar girl who falls in love with a US soldier during the Vietnam War, has been a huge hit and taken millions of pounds at the box office.

The show's producer, Cameron Mackintosh, said: ''I've always known that the public knows best so I am delighted that the new Miss Saigon has swept the board with a record-breaking nine awards including best musical revival and best show, and I'm thrilled for all our other winners as well, especially to the extraordinary achievement of our four leading Asian performers winning the top acting awards.

''The original productions in 1989 bizarrely lost the Olivier Award for Best Musical to a rock and roll compilation show Return To The Forbidden Planet - so it's nice to see the public having the last word.''

The epic musical by Alain Boublil and Claude-Michel Schonberg has been seen in 300 cities around the world and performed in 15 languages. It returned to the West End last year after an absence of more than a decade.

Billie Piper was named best actress for her performance in the National Theatre's Great Britain.

Mark Gatiss, who has both written and starred in Doctor Who, was named best supporting actor for his performance in Coriolanus at the Donmar Warehouse.

Tom Hiddleston, who played the title role in Coriolanus, lost out on the best actor gong to Tennant, but collected the award for best play revival which the play won.