The boom years were 1836 and 1845–47, when Parliament authorized 8,000 miles of lines at a projected cost of £200 million, which was about the same value as the country's annual Gross Domestic Product (GDP) at that time. A new railway needed an Act of Parliament, which typically cost over £200,000 (about $1 million) to obtain, but opposition could effectively prevent its construction. The canal companies, unable or unwilling to upgrade their facilities to compete with railways, used political power to try to stop them. The railways responded by purchasing about a quarter of the canal system, in part to obtain the right of way, and in part to buy off critics. Once an Act was obtained, there was little government regulation. The railways largely had exclusive territory, but given the compact size of Britain, this meant that two or more competing lines could connect major cities.