Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL\
    $^2$ Toruń Centre for Astronomy, Nicolaus Copernicus University, ul. Gagarina 11, 87-100 Toruń, Poland\
    $^3$ Jodrell Bank Centre for Astrophysics, The University of Manchester, Alan Turing Building, Manchester M13 9PL\
bibliography:
- 'ref\_lancaster.bib'
date: 'Received \*\*insert\*\*; Accepted \*\*insert\*\*'
title: 'Sunyaev Zel’dovich observations of a statistically complete sample of galaxy clusters with OCRA-p'
---

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cosmology: observations – cosmic microwave background – galaxies: clusters: individual (A1835, ZWCL1953, A689, ZWCL3146, RXJ1532.9+3021, A2390, A2219, RXJ2129.6+0005, A2261, A781, A697, A1763, A68, A520, A267, RXJ0439.0+0715, ZWCL7160, A773) – methods: observational

INTRODUCTION {#intro}
============

The thermal Sunyaev Zel’dovich (SZ) effect ([@SZ]) is a spectral distortion of the Cosmic Microwave Background (CMB) radiation due to inverse Compton scattering by the hot gas in galaxy clusters. It has long been exploited in cosmological and cluster studies in order to derive, for example, the Hubble constant (e.g. [@Hughes1998], [@Mason_obs], [@Reese2002], [@Saunders2003], [@Bonamente2006]) and the gas mass fraction (e.g. [@Grego2001], [@Lancaster2005], [@LaRoque2006]). Thanks to well developed techniques, detections are becoming routine although signal–to–noise remains quite poor. However, we are entering an era of purpose–built instruments so this is set to improve dramatically, enabling SZ research to reach its evident potential.

