M&C reported turnover of £128.2m, up 1.2% on last time.
The agency won new business including Ribena, ITV, Mini and Tourism Australia during the period, which chief executive David Kershaw described as "encouraging".
Future performance could suffer if it loses its flagship BA account, which it has held for 10 years. The result of the pitch, which sees M&C up against JWT, DDB London and Bartle Bogle Hegarty, is due to be announced in mid-October.
"The underlying business continues to perform well but the outcome of the BA review could have a major influence on the second half and beyond," Kershaw said.
The £4.1m profit figure does not include a goodwill amortisation charge of £821,000, but does account for investment put into the agency's expansion into Europe.
The agency opened a Paris office on September 1 and said plans for an office in either Spain or Germany by the end of the year were well advanced.
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