Swallowtail butterfly enthusiasts flock to Strumpshaw

Butterfly enthusiasts have descended upon an RSPB nature reserve to catch a glimpse of one of the UK's rarest and largest butterflies.

Swallowtails can only be found in the Norfolk Broads.

Diane Scott, from Bletchley, Buckinghamshire, said she was "over the moon" to have photographed the insect at Strumpshaw Fen.

Site manager Tim Strudwick said people come from around the UK to see the "separate subspecies of swallowtail".

Butterfly enthusiasts know they are only likely to see swallowtails from the end of May and into June and come from across the UK

Visitors have "even come from Europe - but the longest day trip is a car full of guys who came down for the day from Edinburgh", he said.

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The insect with its pale yellow wings, black veins and blue margins is a wetland specialist and has a wing span range of between 80 to 90mm (3in to 3.5in).

Diane Scott took quite a few photographs of the swallowtail and was looking forward to going through them all on her return home to Bletchley

It was second time lucky for Ms Scott, who visited Strumpshaw a fortnight ago without a sighting.

"I did see one last year, but it wasn't in that great condition - this one is absolutely brilliant, it's beautiful," she said.

"It means a lot, they're just so special. You don't get them at our end of the country."

The butterfly prefers areas of mixed fen usually dominated by sedge, or sometimes reed - which it can find on the Norfolk Broads

Mick Sharp and wife Jean visited Strumpshaw Fen twice during their holiday before they managed to see the insect

The sighting was "mission accomplished" for Mick Sharp, from Derby.

He and his wife Jean were on their way home after a holiday in Norfolk.

"We tried to see it earlier in the week, but it was too cool, and we've been on a mission to try to see it since," he said.

"It's brilliant - and I was surprised at how quickly it is moving from flower to flower, in a split second it is getting the nectar and moving on."

Mr Strudwick said the insect appears for "quite a short season, from the tail end of May into June."

Butterfly Conservation says the insects like to feed on flowers like thistles and wetland flower Ragged-robin