Some genius has worked out that you will be able to fit 290 million tennis balls into Wimbledon's redeveloped Centre Court once 1,200 extra seats are in and the new, retractable roof is on and closed.

You would also be able to fill it with 7,500 large umbrellas and pump in 143,000 litres per second of conditioned air.

The building work so evident at the moment in one of the world's most famous sporting arenas will also provide wider seats, improved restaurant facilities and, of course, the opportunity to play more matches at the appointed time - come rain or, indeed, shine.

Because, as Wimbledon's PR people Bell-Pottinger point out, the roof - which critics say the All England Club's traditionalists fought tooth and nail to resist over many years - is also designed to protect play and players from all conditions.

But what nobody can tell us, is just how much is it going to cost.

Bell-Pottinger's spokeswomen said: "We honestly can't even give you a guess. Nobody really knows although we have seen plenty of guesses in the media."

Wimbledon Diary is not about to add to that speculation and you might say it doesn't matter anyway because plenty of money comes sloshing into the All England Club and Lawn Tennis Association coffers every year because of the Championships and related items.

But the near-£800million it cost to rebuild Wembley Stadium was a scandal and an ever-escalating price estimate of the 2012 London Olympics is causing major concern in many areas.

And in the end it is the fans who pay for it. Prices of almost everything at Wimbledon this year have risen discernibly and there is much moaning around the courts that certain little courtesies have been withdrawn - and now come at a price.

Also, many people are still labouring under the false impression that Centre Court - currently wide open to the elements while the base of the new roof's structure is erected - will be fully operational for the next Championships.

Not true. Wimbledon, to be fair, have never hidden the fact that it will be the 2009 event before the mobile, concertina-style part of the roof is in place - saving up to a maximum of five matches a day when it rains.

Five might not sound many when it is considered that hundreds of matches have to be played on the 19 other outside courts, but obviously a major boon to providing guaranteed action for home and overseas television coverage.

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No public service announcements at Wimbledon yet to compare with the one during the women's Eastbourne tournament last week when a Mrs Mutton was asked to present herself at the main entrance - no matter, presumably, however she was dressed.

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It is well known that Austria's Sybille Bammer, the number 20 seed at Wimbledon, is the only player on the WTA Tour with a child in tow - five-year-old daughter Tina, who when the lady is not playing or practising is largely looked after by her partner Christophe.

But Bammer, knocked out of the singles on Wednesday by American Laura Granville, is not top tennis' first super-mum by a long way.

Americans Liz Smillie and Lindsay Lee-Walters were often accompanied by their offspring at the major championships.

And, going further back, Australian star Evonne Goolagong-Cawley actually won her singles title in 1980 as a mother.

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The political significance of June 27 was not lost on Wimbledon.

With out-going Prime Minister Tony Blair officially handing over power to successor Gordon Brown, more than a few camera lenses were naturally trained on Downing Street.

Andy Roddick, the number three seed, reckoned it all made compulsive viewing.

"The funniest thing that I saw this morning when I woke up was they televised the moving van literally pulling up, and they followed the moving van down the street when he is moving his crap out. I think that is hilarious," quipped the American.

"We need to get a moving van in the States somewhere. Now, that would be pretty funny."

Roddick, though, admitted: "I am not going to pretend too much to know about the political views of Gordon Brown.

"I think I would be on the verge of ignorance if I touched on that any more - but I am a big fan of the televising of the moving van."