When career con man Roy Courtney (McKellen) and his associate Vincent set their sights on recently widowed Betty McLeish and her millions, a con of jackpot proportions presents itself.

American filmmaker Bill Condon direct Brits Dame Helen Mirren and Sir Ian McKellen in this adaptation of the bestselling 2015 Nicholas Searle novel The Good Liar.

When career con man Roy Courtney (McKellen) and his associate Vincent set their sights on recently widowed Betty McLeish and her millions, a con of jackpot proportions presents itself.

However, as Betty kindly opens up her home and her life to Roy, his conscience is seriously tested and what should be a cut-and-dry swindle turns into a high stakes game of Cat and Mouse.

Amazingly, this is the first time Mirren and McKellen have worked together on screen, their only previous collaboration was on stage in 2001 Broadway musical Dance Of Death. Both are reliably accomplished here.

Mirren stars as Betty the whip-smart grandmother, with a sweet and innocent exterior, while McKellen excels as the despicably callous Roy. His inner turmoil plain to see as he begins to develop real feelings for Betty, and the ultimate goal weighs heavily on his conscience.

Russell Tovey lends support as Betty's suspicious Grandson Stephen and Downton Abbey's Jim Carter takes on the role of Roy's unscrupulous business parter Vincent.

The film's strength is its lead actors. To watch two of British cinemas cherished elder statesmen face off against each other is a delight, the tensely plotted script has treachery at every turn and allows the actors to really have fun with their performances. However in the film's final third, things begin to fall apart.

The Script from Jeffrey Hatcher, makes it very clear there is one final twist in the tale. Yet, when it comes it's so outrageously ridiculous that instead of delivering a triumphant coup de gras, it drags the film swiftly towards farce.

In fact, so out of the blue is the finale, that it seems completely disconnected to all that has come before and will leave audiences utterly dumbfounded.

The Good Liar is enjoyable enough for much of its running time and it is undeniably fun to watch Dame Helen Mirren and Sir Ian McKellen spar with one another.

However, much like the characters they portray, the film's late descent into absurdity will leave viewers feeling rather betrayed.