<sod >Mr Johnson hit out after photographs appeared in the press showing the Rail, Maritime and Transport Union (RMT) general secretary sunning himself on a Brazilian beach while on a cruise holiday just days before the first 48 hour walk-out is due to begin tomorrow.< eod>< sod > Boris Johnson launched the criticism after photos appeared in the press showing the Rail, Maritime and Transport Union (RMT) general secretary soaking up the rays on a Â£10,000 cruise holiday in South America, just days before the first 48 hour walk-out is due to begin tomorrow.< eod>