ASCOT (Reuters) - Royal Ascot kicked off in damp weather on Tuesday, but there were plenty of colorful dresses and hats to lighten up the grey skies at Britain's famed horse racing event.

Racegoers dressed in an array of frocks, including some Union Jack or EU-themed in reference to the upcoming June 23 referendum when the UK will vote whether to remain in the bloc, as well as hats adorned with feathers and floral decorations.

Many attendees were forced to seek shelter under umbrellas to shield themselves from the rain, with some even putting plastic covers on their hats.

The horse racing event runs until June 18.

(Writing By Marie-Louise Gumuchian, editing by Deepa Babington)