He hinted that the it may be two months before the part-time position is filled.
TWA Communications chief executive Wickham announced her departure last week after just over a year in the role.
During that period the tourism industry in the UK has suffered the turmoil of the foot-and-mouth crisis and the aftermath of the 11 September attacks, which saw a stark decline in the number of US tourists visiting the capital.
It is understood that the increased demands on the role caused by the troubles facing the tourism sector meant that Wickham was unable to balance her commitments with TWA and the LTB satisfactorily.
LTB managing director Paul Hopper takes control until an appointment is made. No details are currently available as to what qualities are being sought in the next chair of the body.
The LTB spokesman said that the management board would decide upon the criteria in the coming weeks.
'Because tourism and politics in London have changed so dramatically, we will be talking to stakeholders such as the mayor and the London Development Agency to get an idea of their needs,' he said.
The body is undertaking a major promotional push to build on the opportunities for tourism presented by the Golden Jubilee this summer.
The LTB is also reviewing its strategy on the promotion of tourism in association with the Greater London Authority and the London Development Agency.