Complex sentence: This was due to a change in administration in 1929 that ushered in a minority Labour government under Ramsay Macdonald, which cancelled the ships as an economy measure and a gesture to the forthcoming London Naval Conference.
Split into simpler sentences: This was due to the change in administration in 1929 that ushered in a minority Labour government under Ramsay Macdonald. The new government cancelled the ships as an economy measure and as a gesture to the forthcoming London Naval Conference.