This loco (Hunslet 3883) is notable as the subject of the last formal tests ever undertaken by BR on a steam locomotive with dynamometer car when, in January 1963, it was handed over to the BR Research Department at Swindon for a controlled road test. This took place later that year over an 18-mile section of the Oxford - Worcester line between Yarnton and Kingham. This was to test the Hunslet/Porta underfeed stoker and gas producer system, invented by the Argentine engineer L. D. Porta to help overcome the problem of smoke emissions. The tests on no. 3883 showed significant improvement over a standard Austerity. The maximum recorded output of 898 hp was a very impressive figure for a shunting locomotive.
No idea who Lord Phil is or was, sorry!