Black MP David Lammy described her remarks as 'offensive and ahistorical'.
Nigel Farage and Ann Widdecombe were among MEPs, some of whom were in the European Parliament for the first time.
Its candidate says he is "feeling confident but not complacent".
The Brexit Party and Liberal Democrats have had a night to remember while the Tories and Labour suffered a backlash.
The newly-elected Brexit Party MEP said the results showed people wanted to be listened to.
The move comes after former prime minister Gordon Brown claimed the Brexit Party was a private company with shareholders.