He spent four days in Ulan Bator and two days in a remote central province, in a visit funded by the Westminster Foundation for Democracy.
Mongolia - ruled by ex-communists who an Aiken-drafted report describes as 'seeking to use (their) powers to stifle public debate and discriminate against the opposition' - is quite inhospitable in February, and Aiken received a frosty reception in more ways than one.
He says Mongol TV censored his views and he also found himself deploying PR advice in temperatures of minus 30 degrees. It was so chilly, he says, he coughed up an extra quid to get a radiator in his £2-per-night hotel room.
'It made Serbia seem like Surrey,' he tells Diary, from the relative warmth of his SW1 office.