The school is named for and honours the benefactor William Rutlish, embroiderer to Charles II.

After World War II the school had outgrown its Victorian buildings (and the science block, built in the 1930s, had been destroyed as a result of enemy action) so in the early 1950s, John Innes buildings off nearby Mostyn Road were converted for use as the Junior School.

A new building was planned for the rest of the school, on the present site south of Watery Lane.

To the north is a four-storey main entrance block (which contained the school library on the top floor, and a CCF rifle range in the roof space) and a three-storey central block of general purpose classrooms facing Watery Lane.

The "Manor House" adjacent to the school entrance on Watery Lane was Innes's home; a blue plaque records his association.

Now demolished were school buildings next to the playing field; these were once the library and offices of the John Innes Institution and had ranges of greenhouses attached.

A little-known feature of the old building was a warren of hidden crawlspace passages, accessible from the second floor music room, from where clandestine spying operations on other classes could be undertaken.

Although discontinued for some years, the system was reinstated in January 2010 with eight houses:[6] Various inter-house competitions, often of a sporting nature, are held.