The NER Class P3, classified J27 by the LNER, is a class of 0-6-0 steam locomotive. The P3 Class was designed by Wilson Worsdell and was a relatively minor modification of the existing NER Class P2 (LNER Class J26). The most significant change was a deeper firebox with shallower sloping fire grate. This was achieved by raising the boiler slightly, and by reducing the clearance between the firebox and the rear axle. The P3 Class were a freight engine by nature and used for hauling long trains of freight.

Initially 80 J27s were built between 1906 and 1909 in five batches, distributed amongst the NER's Darlington Works, North British Locomotive Company, Beyer, Peacock and Company, and Robert Stephenson and Company. Twelve years later, a batch of 25 J27s were built at Darlington with Schmidt superheaters and piston valves. These were delivered in 1921-2 and were followed by a final order of 10 placed in December 1922 and built by the LNER at Darlington Works in 1923. The superheated J27s could be identified by their extended smokeboxes.

Withdrawals began in March 1959, but in June 1966, thirty-six were still going. The last J27 was withdrawn in September 1967. One, BR 65894, has survived to preservation and was purchased directly from BR by the North Eastern Locomotive Preservation Group on 1 December 1966.