But at a more junior level, returnees can sometimes have problems reintegrating, may lack local market knowledge and are expensive.

ECONOMIST: Human resources

Matters seemed to be improving as Bernard won his maiden ATP title in January but this latest incident appears to be yet another setback in a stop-start career for a player with a fine record at junior level.

CNN: Tomic Snr claims self-defense for Drouet clash

In one study, they did online surveys of 208 incoming business graduate students who had been working as junior to mid-level managers at a range of companies, including health care, finance, manufacturing and pharmaceuticals.

FORBES: Bosses Don't Listen: Now There's Proof

It would be unusual for a junior minister to be promoted to cabinet rank without a spell at minister of state level but these are unusual times.

BBC: MPs and "armchair reshufflers" ponder cabinet changes