Today all eyes will be on the jockeys' silks, but yesterday Aintree was all about other kinds of fabric

It has been a long, cold winter, so perhaps it was not surprising that when an opportunity to wear the bright colours of spring presented itself, the women of Aintree embraced it wholeheartedly. The scene at Ladies' Day yesterday wasn't so much a riot of colour as a full blown revolution: magenta, fuchsia, acid yellow, hot pink, lilac – and that was just in one outfit.

The glamour provided a suitable warm-up for today's Grand National, on which bookmakers estimate Britons will wager a staggering £250m. The 4.15pm race is only one part of a bumper sporting week for the bookies, with £1bn expected to be bet on the horses, Tiger Woods' return to golf at the Masters, and the semi-finals of the FA Cup.

The first surprise of the day was the sober garb of Wayne Rooney's wife, Coleen. She had been expected to wear spring colours, with bookies taking bets on her wearing pastel tones, but the 24-year-old arrived at Aintree with her entourage in a black dress with silver trim.

One of those enjoying themselves in the sunshine was the racing pundit John McCririck. He said: "The Merseyside totty believe in flaunting themselves and it is tremendous, not like at Royal Ascot with their haute couture and the toffs and the designer outfits. They have much more curvaceous bodies here and are magnificent, especially with the sunshine coming out."

Orange proved a popular choice, and there was pattern too in the form of animal prints, florals, swirls and tie-dye. Those such as Mrs Rooney who chose black might have been accused of playing it safe, but managed to look more sophisticated than the average racegoer.

Perhaps it was the lure of a £7,500 prize for the year's most stylish lady that made some guests try so hard, even if it was dramatically less than the Caribbean holiday, car and photo shoot worth a whopping £35,000 up for grabs last year.

The best outfits at the event were the more restrained ones. The girls pictured wearing yellow and blue managed to combine spring-like shades with cleaner shapes for a look that's sweet and young. Similarly, their more demure necklines, compared to some of the daring cleavages on display, meant that trainers or punters might actually be able to keep their eyes on the races.

When it comes to summer events in Britain there are some garments and themes that will always emerge, regardless of trends, and the maxi dress is one of them. This season, however, maxis also happen to be on the catwalks, appearing in pale floaty fabrics at Chloe and Alberta Ferretti, although the versions at Aintree were generally more plunging and embellished than bohemian and ethereal.

Another recurring theme is guests' tendency to co-ordinate their outfits with one another, with one pair even wearing the same dress. Similar clothes weren't the only thing they had in common, though: almost everyone appeared to be having the most fun you can have with your – very colourful – clothes on.