The Kate Effect, all over again

When she first wore it that famous phrase 'the Kate Effect' hadn't even been coined. Now it's all but an officially recognised phrase. And it will no doubt be mentioned many times in the next few days as word spreads that the dress Miss Middleton wore to announce her engagement to Prince William is back on sale again. She might be a duchess now but this is still a Kate frock.

It's back and this time it's still blue - Kate wears the Issa dress that keeps on giving

The dress barely needs describing, it's so famous. It's navy blue, in case you hadn't noticed, with a flared knee length skirt and a pleated top with a banded waist. It's silk, it's by Issa and it sometimes goes by the name of the Phylis. But mostly it's called the one that Kate wore when she got engaged. It's about as famous as a frock gets.

View image | gettyimages.com

The company which makes the global superstar of a dress announced on Twitter that the Kate Effect was back with a bang. The gown, costing £575, is available at Harvey Nichols - where else? - and will no doubt fly off the shelves just as it did back in 2010. The company's website suggests adding silver jewellery - Kate didn't need to, she had that famous sapphire and diamond ring on her finger. Copying that might be harder work.

First seen on the Duchess of Cambridge, @IssaLondon's Phylis dress tops our wish lists: http://t.co/VFWRzBXJLp pic.twitter.com/HTFnigqlkO

— Harvey Nichols (@HarveyNichols) July 16, 2015

And while we probably won't see that much of the duchess before the autumn - there is an engagement this Sunday though - there's no doubt that her influence on fashion remains strong. So strong, in fact, that a dress she wore just once almost five years ago is topping shopping wish lists even now.