The final episode of the Olympic-themed mockumentary is as clunky as the rest. The satire isn't sharp enough and the comedy feels forced. But it's not the fault of the actors: Jessica Hynes is on fine form as branding exec Siobhan, negotiating to cover Anish Kapoor's Orbit Tower with a special wrap sponsored by a condom company, but when the accompanying rap video goes viral on YouTube the team threatens to alienate every single Catholic competing country. Meanwhile, Karl Theobald delights as hapless Head of Infrastructure Graham, forced to re-design the Olympic Torch Relay route so that it goes beyond Surrey.

This episode of the lovingly detailed comedy of errors could almost have been written by cutting and pasting actual newspaper articles.

Because the latest hurdle for Ian Fletcher's Olympic Development Committee concerns the (still unresolved) post-Games future for the Olympic Stadium and the rival bids from West Ham and Spurs.

A football pitch with a running track around its perimeter? Who wouldn't want a white elephant like that?

What the cast bring to this series are the glimpses of barely concealed panic just behind their eyes and Sally Hope (Amelia Bullmore) is absolutely marvellous this week - toiling through the night to produce her report on the Spurs bid and their manager Harry Houdini.

The other major development this week is that super-PA Sally has abandoned ship, after Ian (Hugh Bonneville) failed to turn up at her house last week, and has been replaced by a sweet boy called Daniel.

Meanwhile, Ian and Siobhan (who is frankly too thick to panic) are off to Clarence House to thrash out ways the Queen's Diamond Jubilee and the Olympics can pull together.

And that means a visit to the "Ideas Space" at Siobhan's PR company. Like Siobhan, it's a room which manages to be vacuous, loud and pretentious all at the same time.

We get a glimpse into the workings of unspeakable PR agency Perfect Curve when dead-eyed Siobhan (Jessica Hynes) gathers her team to brainstorm ideas. They come up with a terrific wheeze - combining the Queen's Diamond Jubilee with the Olympics. Result? The Jubilympics.

Back at the Olympic Deliverance Committee offices, Ian has an attentive male PA, and febrile head of sustainability Kay Hope (Amelia Bullmore) is quietly in meltdown. There's a wonderful scene between Kay and Ian (Hugh Bonneville) after Kay has a moment of madness with a vitally important document.

Twenty Twelve delivers quiet chuckles rather than belly laughs, but that's not to underestimate the subtle humour that mostly hits the mark. Much of the wit lies in the small details: from the gruesome multi-coloured logo to the ubiquitous fold-up bikes that are fast becoming a visual running gag. There's much merriment to be had tonight from the Perfect Curve PR team, led by clueless head of brands Siobhan (a superb Jessica Hynes) and including a 'viral concept designer', called Carl Marx. Elsewhere, Hugh Bonneville's performance is as beautifully nuanced as ever, juggling 'sustainability', 'legacy' and - this week's catch word - 'inheritance'. 'Who knows what that shit is,' says Siobhan when told she has to come up with a concept to combine the three. Indeed.

Top of the agenda in this neatly played Olympics satire is what happens to the stadium after the last closing ceremony ribbon-twirler has turned the lights out. It's an issue that poor Hugh Bonneville must navigate in a meeting that involves random shout-outs of 'Hammers!' We also get to see inside the office of Perfect Curve, the moronic PR agency run by Jessica Hynes's brilliantly hideous Siobhan Sharpe. Their branding solution to link the Queen's Diamond Jubilee with the games? 'Jubilympics'.

Another episode of the "mockumentary" following the work of the Olympic Deliverance Commission that will leave viewers wondering just how fictional it actually is. Set early in 2011, it sees Head of Deliverance Ian Fletcher (Hugh Bonneville) trying to find the right buyer for the Olympic stadium. "It's crucial that the decision process is impartial and fair at every stage," he tells his colleagues. "At the same time, if being impartial and fair did end up favouring the West Ham bid, that would be no bad thing."

Twenty Twelve, BBC Two, review

If Twenty Twelve's creators were looking for inspiration for their mockumentary about those making London 2012 happen, they need have gone no further than reading the headlines (now daily) in London newspapers about Tube drivers demanding more wedge to work during the Games, the Civil Service asking their staff to work from home and the London Mayor's transport officials suggesting that August may be a good time to find an alternative route to work - this after Londoners have put up with years of delays and cancellations while the system was being upgraded not for their benefit, but for visitors to the event.

It looks as if the dozy Olympic compromise to keep the Algerian team happy this week in BBC2's sitcom Twenty Twelve (10pm).

But a potential boycott - initially triggered by the Algerians' fury that the Olympic Village's religious centre doesn't face Mecca, now threatening to start a domino effect that could scupper the whole Games - is the least of committee chief Ian Fletcher's worries.

Not only is his estranged wife giving him grief, but Sally, his irreplaceable but sadly besotted PA, is about to quit.

The Olympic Deliverance Committee, a bunch of people who do an awful lot of talking yet somehow never manage to say anything. Take half-witted PR flack (sorry, Head of Brand) Siobhan (superb Jessica Hynes), whose contributions to meetings begin and end with "I'm totally good with that" and who thinks Canterbury (as in the Archbishop of) is in Sussex.

As the row over the faith centre escalates, there are discussions about whether the Olympic Village laundry centre could be converted into a mosque to appease the Algerian team. Siobhan and Ian Fletcher (the great Hugh Bonneville) have a painfully funny on-site meeting with an exasperated architect at the end of his tether. It's another layer of tortuous bureaucracy as everyone strives for a "beacon of inclusiveness".

Is it just us or is Twenty Twelve getting funnier as the Olympics draw nearer? After all, it's not impossible to imagine a real-life row about a faith centre escalating into a frenzy of stubborness and obfuscation. Tonight, the Algerian boycott threat comes to a head with all manner of compromises - including a six-sided building and a retractable minaret - being considered. Sadly, the team is also prone to getting side-tracked by - for example - whether hand dryers are a legacy or sustainability issue. The performances are brillliant - particularly Jessica Hynes's unbearable Siobhan and Olivia Colman's devoted Sally - and the script is pitched perfectly between fondness and scepticism. If we Brits are good at anything, it's taking the piss. Particularly out of ourselves.