10 p.m. Ugh. Perpetua, slightly senior and therefore thinking she is in charge of me, was at her most obnoxious and bossy, going on and on to the point of utter boredom about latest half-million-pound property she is planning to buy with her rich-but-overbred boyfriend, Hugo: 'Yars, yars, well it is north-facing but they've done something frightfully clever with the light.'

I looked at her wistfully, her vast, bulbous bottom swathed in a tight red skirt with a bizarre three-quarter-length striped waistcoat strapped across it. What a blessing to be born with such Sloaney arrogance. Perpetua could be the size of a Renault Espace and not give it a thought. How many hours, months, years, have I spent worrying about weight while Perpetua has been happily looking for lamps with porcelain cats as bases around the Fulham Road? She is missing out on a source of happiness, anyway. It is proved by surveys that happiness does not come from love, wealth or power but the pursuit of attainable goals: and what is a diet if not that?

On way home in end-of-Christmas denial I bought a packet of cut-price chocolate tree decorations and a ?3.69 bottle of sparkling wine from Norway, Pakistan or similar. I guzzled them by the light of the Christmas tree, together with a couple of mince pies, the last of the Christmas cake and some Stilton, while watching EastEnders, imagining it was a Christmas special.

Now, though, I feel ashamed and repulsive. I can actually feel the fat splurging out from my body. Never mind. Sometimes you have to sink to a nadir of toxic fat envelopment in order to emerge, phoenix-like, from the chemical wasteland as a purged and beautiful Michelle Pfeiffer figure. Tomorrow new Spartan health and beauty regime will begin.