Hello and welcome to today's independent travel podcast with me Simon Calder. I'm in beautiful

Copenhagen. There will be some people who are here and don't want to be, but their flights were

cancelled among the 2000 or so flights grounded that we have seen since the air traffic control

failure for four hours on Monday.

And I've been looking into this trying to find out what the heck happened and what is going

to be done to avoid it happening in future, which of course is what we all want to understand.

And I've had a long chat with

Martin Rolf. He's the chief executive of NAS, the air traffic control service for the UK.

And of course they have extraordinarily complex and very sophisticated computer software that is designed to allow the controllers

safely to handle a fantastic amount of air traffic maybe 8,000 flights a day going to through over

UK airspace.

And while the shutdown was four hours from quarter past 11 until quarter past three in the afternoon,

we saw very significant problems coming up before that.

And they apparently spotted the problem at half past eight.

So what was the problem exactly? That's what people have been speculating about.

And it all centres on a rogue flight plan. That involved, it is said said a French airline putting in a flight

plan which is a very routine thing and that handles a couple of millions of

them every year and this one wasn't in the usual format so what did the

system do?

It looked at it and thought, well, this doesn't look right.

And we certainly don't want to send this on to the controllers

because they might act on false information.

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