Could this be a swallow tailed kite?

My friend saw this bird in Evington Park and took the enclosed photograph.

On the identifier it says it is a red kite, but because of the white markings, he thought it might be a Swallow Tailed Kite.  If it was a swallow tailed kite, this would be very rare.

Is it possible he saw a swallow tailed kite?

Helen