In a letter to shareholders accompanying its defence document, Newman Tonks' chairman, Christopher Hughes, also attacked the decision by M&G, its largest shareholder, to back FKI's bid.
"I am very disappointed that M&G should have made this decision without speaking to us first," he said.
"We had taken care to maintain a regular and responsible dialogue with M&G in recent years and their action is not consistent with the understanding that we believed we had with them."
M&G, which has a 11.2 per cent stake in Newman Tonks, gave irrevocable undertakings to accept FKI's bid on the day it was launched.
Newman Tonks also played on concerns that FKI might be overstretching itself, having spent pounds 260m in three deals last year. But FKI hit back, noting that Newman Tonks' share price had fallen by nearly a third in five years under the current management.
"How Newman Tonks' board can say that it has delivered a strong financial performance... is simply incredible," said FKI's chairman, Jeff Whalley.Reuse content