Just what the BBC viewers' reaction will be to three programmes in August showing progress of Olympic construction is anyone's guess. A tour round the 600-acre moonscape lthis week certainly impressed. Had Kevin McCloud been filming, the shots would be inserted about 11 minutes into a Grand Designs special for transmission in August 2012.

That is because the Channel 4 programme works to a fixed emotional timetable. Pessimism: planning woes, budget worries and pre-construction fears - 10 minutes. Optimism: work begins, it's all taking shape, look mum! - 20 minutes. Despair: it's taking too long, costing too much, the builders are hell - 20 minutes. Delight: it's done, its lovely, oh never mind the budget - 10 minutes.

The Olympic park programme is on the cusp between the pessimism and optimism phase.

A few half-hearted kicks over the ballooning budget were duly administered this week, after the price of the Velodrome doubled to £80 million. But almost-formed plans to shift the fencers to ExCel in the Royals and weightlifters to O2 in Greenwich will save a good bit of that extra cost.

The £9.3 billion budget will rise again in importance during the despair stage, or maybe not, if construction prices follow the economy down.

Work on the main stadium began last week. That is three months early, pointed out tour guide John Armitt, chairman of the Olympic Delivery Authority.

"Life will not be all sweetness and harmony over the next three years. So every day we gain now is a bonus," he said. This will no doubt be pointed out to the International Olympic Commit-teewhen delegates come to London on 22 May for an inspection.

There is even talk of Gordon Brown putting in his first appearance; optimism indeed.

What the ODA calls the "Demolish, Dig, Design" phase began in April 2007 and finishes this summer.

It has left the place a shallow open-cast pit the size of 357 football pitches populated by dump trucks, diggers and, something relatively new to a building site, a spoil sorter.

This machine sorts much of the 1.3 million tonnes of excavated material into big lumps, small lumps and sand at a rate of 500 tonnes a day. Around 85% will be re-used.

The tour was admirably spartan; no builders' tea, not even a biscuit. Remember, the budget.

At one point the bus bumped and jolted past a huge flat oval. Here the main stadium builders Sir Robert McAlpine have just set up a three-storey camp for 300 staff. They will toil under the faintly embarrassing title of Team Stadium.

This is the beginning of phase three. The Big Build, as the ODA calls it. Work on the stadia, the aquatic centre and the 4500 homes to house the athletes must be finished by the summer of 2011.

So must 1.3 million square feet of space for an even pickier audience, 20,000 or so of the world's media.

This one structure is still sadly in the first five minutes of its grand design programme.

Builder Carillion and developer Igloo have signed up to build this monster. But it has no real post-games use - as a media centre that is..

At a stop on the road opposite the location Armitt suggests perhaps "20-30%" might be pulled down and homes and shops built on the land. And that some of the rest could be converted into storage sheds. "It's right by the A12," he suggests, optimistically.