Numerous companies will likely follow prominent UK advertising firm WPP Group in relocating their headquarters abroad amidst tax concerns in the country, WPP Chief Executive Martin Sorrell has announced, the Financial Times reported Monday.

The firm recently became the sixth and the largest company to move overseas when it moved to Ireland due to the “complexity” of the UK tax policy, reported the Financial Times. Modifications to the taxation on foreign revenue may augment the tax costs of companies that gather large portions of revenue from abroad, according to Bloomberg.

“It's clear from what I have heard that the government must rethink its strategy on taxation, as many council members reaffirmed that the current system is highly likely to drive more great wealth-creating enterprises like Sir Martin's WPP to base their headquarters overseas where they feel the tax demands are fairer,” said UK's Mayor Boris Johnson, according to the Financial Times.

Prime Minister Gordon Brown reduced the corporate tax rate from 30 percent to 28 percent while he was finance minister in March last year. However, he was criticised for moves such as the taxation of foreign dividends and the restructuring of the charges of capital gains, according to Bloomberg.

WPP showed concern over the Treasury's recent plan to modify foreign profits taxation, which risked preventing nearly £1 billion of the country's tax revenues from going abroad. According to the Financial Times, such legislative measures were aimed at firms like WPP, which deal with intellectual property on a bigger scale. The WPP, meanwhile, said that such a change may have caused its tax costs to increase by “tens of millions of pounds.”

The plans were dropped this summer. However, if they would have gone forward, multinational companies would have seen their global “passive income” (like gains from intellectual property) being taxed. The Treasury assured that it does not intend to increase revenue gains from businesses and that the reform plans were caused by the multinationals lengthy demand to be let off from taxes on repatriated foreign dividends, the Financial Times reported.

Wire and Plastic Products was established as a producer of wire shopping baskets in 1971 and bought by Martin Sorrell in 1985, after which he renamed it to WPP Group.