Mr Brown was chancellor at the time of the Iraq war
More than 300 people applied for seats at Gordon Brown's evidence to the Iraq Inquiry - but only one family who lost a relative was among them.
The 323 entries received for the PM's session on 5 March is considerably fewer than the 3,041 who applied to see his predecessor, Tony Blair.
Mr Brown's evidence is being split into two sessions - with 60 seats at each.
More than 150 extra seats will be available - people granted seats will be told in the next few days.
Mr Brown, who was chancellor at the time of the 2003 invasion of Iraq, is likely to be asked about evidence given by previous witnesses about military spending and his role in events.
He has said he is happy to give evidence ahead of the general election as he did not want people to think there were any "unanswered questions".
He told the left-leaning Tribune magazine this month the threat of weapons of mass destruction had not been the main reason he backed the war - it was Iraq's disregard for UN resolutions which had "put at risk" global security.
When Mr Blair gave evidence 40 seats were allocated for the families who had lost relatives in Iraq.
There was due to be a separate ballot for families for Mr Brown's appearance but in the end only one applied.
In total 243 people will get seats to see Mr Brown - either during one of the sessions in the evidence room or in a separate viewing room.