Did Royal Enfield prototype go racing?

Did a prototype Royal Enfield café racer go racing? 
The answer may be in a book. 

I was in for a surprise. 

I did my recent blog item about the Royal Enfield Interceptor Series II Sports Prototype of the late 1960s believing that it was just a last-ditch styling exercise before Royal Enfield went out of business in the UK. 

Shiny fenders, full instruments and lights, and even a horn, suggested this café racer was speed for the street, not the track. If the Sports Prototype had been produced it would have been a very early lookalike for today's Royal Enfield Continental GT 650.

But maybe the Sports Prototype was something else again.

"Wasn’t this the production racer that Royal Enfield did?" Allan Hitchcock replied when I asked him about the bike. 

"I think either Richard Stevens or Ray Knight rode," he wrote in an email. "I don’t know a lot about it but I think there is a decent article in Andrew Stait’s Interceptor book." 

What?? Did the Sports Prototype go racing? 

Photographs show that the Interceptor Series II Sports Prototype was a dead ringer for the Production Racer photographed at track events. 

In his 2005 book "The Mighty Interceptor, Royal Enfield Interceptor 1962-1970," author Andrew Stait includes the racing recollections of riders Richard Stevens and Ray Knight.

Stevens was on the development staff at Royal Enfield. Knight was a successful winner in Production Racing events.

Photos in the book show the Royal Enfield Interceptor Series II Production Racer wearing the same road going equipment as seen on the Sports Prototype café racer. The rear-set bits might vary (hard to tell) but the rear bum and its piping and other details look near identical.

The Royal Enfield Interceptor Series II Sports Prototype.

Could it be the same bike?

The Royal Enfield Interceptor Series II Production Racer.

Bob Murdoch, Royal Enfield Owners Club (UK) archivist, provided the photos of the Series II Sports Prototype. I asked him about the resemblance to the Production Racer.

"It's quite possible that it's the same racer, or perhaps parts of it used on the racer. Bear in mind that Enfield Precision at Upper Westwood was a very small hand-to-mouth concern, and nothing would have been wasted or cast aside if it was suitable for use on another bike. Competition machines were often sold to employees, used as staff transport, or detuned and sold to the public."

One common element, the connection to designer Reg Thomas, is absolutely clear.

Richard Stevens writes: "Chris Ludgate, the development engineer and myself managed to convince Reg Thomas, chief designer of the Series II bike, to use one of the Interceptors in Production Racing to further develop the machine at racing conditions."

Stevens and Knight took the Royal Enfield Production Racer to Snetterton Circuit, a one-time RAF base converted to racing in the 1950s.

"The test would have just the opposition to give some answer to the question of how good Reg Thomas's new beast is," Knight wrote.

The exciting full story (and much more) is in the book, but it's fair to say the Interceptor Series II Production Racer had a good day.

Stevens recalls that "winning Club level races and the Bantam Racing Club Production was pretty pleasing for me and the management and staff at the factory."

Royal Enfield production, though, was at its end in Britain, "with the factory closure and the racer being sold off," Stevens concludes.

Does the motorcycle still exist somewhere? If so, it has quite a history.