Visited with TC in very heavy rain.
Opening in February 1960, Market Weighton ROC was used by the Royal Observatory Corp. Their role was to report nuclear bursts and monitoring fall-out. This is one of 1563 underground monitoring posts throughout Great Britain and Northern Ireland. Surface features look decent, although the hatch is missing.

Much of the shaft is wet (fnaar fnaar)

Inside the monitoring room is surprisingly dry.

On the top of the cupboard was a few pages from the Bible and a rusting can of Racasan, a toilet chemical. It tasted horrid.

I didn't try the toilet chemical in here. In fact I didn't try anything at all in here.

This post closed in October 1968, although many remained until 1991. They always look very bright these places (flash usually, or a bright lamp or torch) but they aren't. A last shot from in the monitoring room before heading out into the pouring rain.