This paper describes the P-y type model that was developed for designing piles in chalk at the Westermost Rough Offshore Wind Farm located in the UK Sector of the North Sea. This wind farm comprises 35 turbines supported on large 6.5m diameter monopile foundations in water depths of approximately 20m. During the design process, it was established that the chalk at Wester most Rough had similar properties to the chalk present at a pile test site in Kent. Results from pile testing at this site demonstrated the criticality of ensuring that the response of the zone of remoulded chalk created along the walls of the piles during pile driving was properly incorporated into the P-y model. A number of plate driving tests were performed at the test site, with post installation excavation of the plates allowing the disturbed chalk zone to be measured for inclusion in the design approach. The model was then integrated, along with conventional P-y curves for the surface quaternary sands and clays, and received certification from DNV.