The Victor and Vulcan Mk2s had a rapid start system. It was known as combust start on the Victor and ripple rarid start on the Vulcan. I can't speak for the Vulcan system, but the Victor system worked like this.
The aircraft would be 'combat checked' i.e. all checks up to engine start already completed. On arrival, all the crew had to do was strap in and commence the start sequence. All four could be started at once. On selection of start, the contents of a high pressure air bottle were fed into the 'combustor' which was a cylinder with a perforated piston, one side of the cylinder contained fuel, the other side is where the air went in. The air forved the piston down the tube, the fuel was pushed through the perforations and atomised. At some point, the mixture was ignited and the results fed into the air starter motor. This wound the engine up to 75% rpm in a matter of a handful of seconds as the generated pressure was in the region of 300psi - normal air start pressure was 30. the exhaust was fed out under the engine and was pretty impressive to say the least.! On QRA scrambles, it was the groundcrew's responsibility to make sure they were not under the wing once the door had been shut. If they were and the 'tit' was pressed, it was curtains.
On the tanker version we still had it installed, but only on engines 3 and 4. It was handy at civil airfields when there was no goroung power available and we could start on battery power alone. Although a careful briefing to ATC was useful - otherwise you would attarct the attention of the airfield fire services fairly quickly.
The Vulcan ripple rapid started the engines in sequence - hence the name. I think it could be started from a button on the noseleg - a former 'flatiron' driver will no doubt confirm or 'pooh pooh' this.