We checked the weather with the super-co-operative Arctic Weather Service based in Edmonton (they've got used to our British voices enquiring politely into what weather might be occuring at unlikely places of interest on the Arctic Ocean); and have been remarkably accurate given the infrequent and patchy satellite data attainable north of 88N. At 09.00 with an updated satellite image due shortly it still looked overcast and ice fog-bound. The decision then understandably had to be made for one aircraft to head south on other missions. At 11.00 Delta came up with 'we're sunbathing under clear skies'. Too late! A full complement of two aircraft at Eureka would not now be possible until 08.00 on Saturday morning. Nightmare! (And that's the drastically compressed version of all the logistical considerations that have to get factored into the final solution). At 17.00 the Arctic Weather Service reports a thin triangle of almost cloudless skies stretching from Alert (the military station located on Canada's northernmost coast) across to 90W and up to 89N. It looked like it would hold for at least six hours, possibly 12 hours; beyond that it was more a case of 'Do we feel lucky?' We needed it to hold for 20 hours.

The problem. We had to give the go-ahead and fly all the way to 88 10N regardless of whether a landing/change-over was possible because Delta had now eaten their last meal the previous night; so an airdrop to them of food and fuel was now necessary anyway. But the timing of the take-off of the planes was absolutely critical (and yet we had so little information to go on) because it dictates the timing of any and all the landings (some 4-5 hours later); and yet if we missed the window of opportunity offered by this thin slice of weather (with building cloud sytems threatening to envelope it from the west and east) at the planned landing sites, the project could have faltered there and then: it would force an extra, and substantial unbudgetted, air charter to put Echo down another day; and that delayed change-over could have meant that Echo were doomed to run out of time to reach the Pole before the ice broke up.

Meanwhile Penguin Echo, who were being royally housed, fed and watered by a rarely visited Canadian organisation based at Eureka, had been coping extremely well with their 24 hour stand-by status. They were making short daily forays into the hinterland spotting all manner of animal tracks including polar wolves, musk ox, ptarmigan and Arctic hare and, to their astonishment, actually saw a single lemming going manically about its business in the fast-thawing snow (+4C). It's tough to cope in these circumstances. The mind goes into a sort of 'limbo-land' or 'neutral gear' otherwise one would go mad with frustration; but when the time comes, one must be able to switch fully on to the challenge ahead - and that can be a difficult and all too abrupt phase; and there's nothing worse than going down onto the ice, perhaps for the biggest challenge of one's life, in a 'half-baked' state of preparedness.

However it would be hard to imagine a team of individuals better suited to what lies ahead. No fudging, it's either the Pole or it's not when they come off the ice - and they have no illusions about the enormity of the responsibility they feel towards their fellow relay squad members who have put them at over 88 North against considerable odds.

At 08.00 (Saturday) the planes take-off. Weather looking excellent. 10.30. Delta report overcast conditions closing in - pilots report low cloud at the refuelling point. The fuel plane makes it down. Echo continue on north in closing gloom. The pilots make a skilful landing in difficult conditions. The change-over is ON. While the appointed person from each team quickly but calmy orchestrate the complex exchange of equipment, clothing, rations, repaired items, spares, batteries, mail, film and video stock etc (and it's high pressure stuff - a single error easily costing the whole project the Pole) the others continue to improve the airstrip. And before you know it, doors are being pulled shut from the inside of the aircraft, propellors are whirring, snow is being whipped into a storm as the engines revv up and within seconds your on your own 109NM (Delta drifted 1NM north on their last night) from the North Geographic Pole. A quick confab with the two intrepid guides - Matty McNair and Denise Martin - and their on their way.

We know they set off (at about 14.00 today after the change-over) as they mean to continue - long days and fast miles. As this update was going out their Argos transmission came through as 88 20N, 75 26W with a status code of 'All OK' . So 315NM down, 100NM to go; and the very best of luck to Caroline Hamilton, Pom Oliver, Lucy Roberts and Zoe Hudson.

More pictures of Delta.