The five-year deal extends a partnership that started two years ago when Air Business managed UKIP's magazine distribution and then took on fulfilment, despatch and return of direct mail, said the latter's managing director Graham Johnson.

He said UKIP Media and Events had made hardcopy mailings a key part of its acquisition strategy as email responses had been declining. Its new focus was on magazines, mostly in the transport sector, and direct mail marketing campaigns.

"No one ever said an email was beautiful, which is why we are investing more and moe in print," said Johnson, who runs around 30 magazines and 30 shows globally."Our print runs are increasing. We have probably done about 20% more print this year than last and we expect another 20% in the coming year – a 40% increase in two years is big.

"People think it's cost effective sending email. It is very cheap but the most expensive way of marketing in the world if no one comes to the event. The power of the letter has increased enormously. Email was effective before but now it doesn’t work, you may save costs but email is poor value for money as you don’t always get results.

"A beautifully presented, signed invitation will get a reply and our five-year contract reflects that. We fully expect our relationship with Air Business to grow, continuing beyond five years, as our mailings grow. We will be mailing more in five years than we are today".

Air Business group managing director Adam Sherman: "Despite the increasing size of Air Business the customer remains at the forefront of everything we do. Our tailored solution has cemented our relationship with UKIP Media and Events."