Speaking in front of roughly 200 people at the Canada-United Kingdom Chamber of Commerce, Couillard boasted about his government's plan to develop Quebec's northern resources and to relaunch the maritime sector.
The premier also criticized his main political opponents, the separatist Parti Quebecois, without mentioning them by name.
He said his government's "political orientation" doesn't require that he constantly reassure investors.
"Every time there is a file that could bring up the subject of a Quebec referendum, it worries investors," he said. "It would be naive to claim otherwise."
Last year's debate in Quebec about secularism was "an odd choice" of priorities, he said, adding his government prefers to talk about the economy.
The United Kingdom is one of Quebec's major economic partners and trade between the two equalled $4.8 billion in 2013, a 10 per cent increase over the previous year.
London was the first stop on Couillard's 10-day European tour, which will see him visit Belgium and attend the World Economic Forum in Davos, Switzerland.
Couillard said the goal of his trip is not necessary to close specific business deals, but to "make links."
He reminded reporters that FerroAtlantica's decision to build a silicon factory in Quebec started from informal discussions three years ago in Davos between then-premier Jean Charest and the company's head.
These business trips "open doors," Couillard said. "If you can finish deals even better, but (the trips) are for making contacts."
The premier spent time Thursday meeting with the staff of The Economist magazine and was also scheduled to visit with Bloomberg journalists to offer details about how his government will balance the budget."
"I want (Bloomberg and The Economist) to understand our reasoning," he said. "They are opinion leaders. An article in The Economist on Canada and Quebec will be seen around the world. Readers will develop an idea of what's going on in Quebec."