I tried to wriggle out of it by pleading recently fallen arches, but there was no escape if I were to cling on to any vestiges of credibility. Training shoes were bought, feet were hardened in salty water and a date was set.
After a couple of 10-mile training walks to prepare me for the rigours ahead, I set out on the long road from Peterborough to Middlesbrough nine days ago, accompanied by my dear wife, who herself can set a fearsome pace, and followed by a Land Rover containing a quantity of medical and nourishment provisions that would not have failed Hannibal and his elephants as they set out across the Alps, had "isotonic body fuel that keeps you going 33 per cent longer" been invented in those days. The local panto dame, exquisitely made up at 7am, chased me off, waving his/her handbag.
The A15 no doubt solves a vital purpose. It leads to the Humber Bridge, which plays a significant role in the transport infrastructure of our great nation. But Route 66 it ain't, and the only place-related song title I could think up during my four arduous days plodding alongside 35 tonne trucks as they shuddered by was "24 hours from Scunthorpe".
A little old lady did come out of a fairly modest house in the village of Baston to give pounds 4. I had promised to walk the 184 miles to promote mental health charities.
The one saving grace on the A15 is the beautiful city of Lincoln. I spied the magnificent cathedral, which dominates the surrounding lowlands, at about half past one on Sunday. Unfortunately, two hours later, I was still making my approach, plodding laboriously up the cobbled road that bears the painfully apt name of Steep Hill.
If nothing else, Lincolnshire must boast a record number of RAF camps. We stayed overnight at one. The road sign warned "Beware, camp entrance", so I tried very hard not to mince in.
We thankfully moved into new territory on day five, joined by Ray Stubbs of BBC TV and Mike Amos of the Northern Echo. The countryside on the road from Beverley to Norton, near York, was improving, but, despite the excellent companionship of the two reporters (who didn't take kindly to walking past pubs) it was a long, hard day. We stopped walking at three o'clock, the morning sweat having long since turned our shirts to damp rags, and repaired to The Whistle Stop on Malton Station, the most wonderful cafe in the western world: Monet prints on the walls and a superb array of cakes and rolls to follow a warming bowl of soup.
Now at this point I should impart some tips to anyone thinking of embarking upon a similar walk: 1. Make sure to take off your woolly mitt before dunking your mid-morning digestive biscuit, or you'll have cold fingers for the rest of the day; 2. Be very careful when approaching a lorry in a lay-by, because the trucker may simply have stopped for a pee and will not appreciate your brandishing a bucket in front of him.
Peter Warren, from the Football Supporters' Association, carried the bucket from day six. Day seven, the penultimate day, and nearly there. Despite the blustery weather, the North Yorkshire Moors and Cleveland Hills provided a bleakly beautiful backdrop and the locals who had heard of our efforts were only too pleased to stop the car to contribute. I made a vain effort to shepherd a stray sheep to safety. For the one and only time on the walk, we briefly entered a pub. The landlord said: "Good morning, Mr Mellor."
The final day dawned brilliantly, a fierce yellow sun peeking out from behind the hills to promise a hint of warmth against the chill wind. Along the way Boro supporters and supporters of the charity Mind swelled our numbers. We met the mayor of Middlesbrough, who walked, minus his robes mostly, for the final six miles.
The Riverside Stadium, albeit standing in something of a wasteland, is not a bad-looking arena. To me, on Saturday as I emerged from the underpass, it could have been St Paul's or the Sistine Chapel - it was a wonderfully welcoming sight.
Football being what it is, the match itself was a goalless draw with few redeeming features and Juninho, to the bewilderment of the fans, was substituted by, with all respect, the less-gifted Robbie Mustoe in the second half.
Never mind, it had been a memorable week and the little Brazilian presented me with a Boro shirt emblazoned with "Kelly 184 miles" on the pitch before kick-off.
Many thanks to all who contributed.