Foreign secretary William Hague refused to confirm or deny claims to the UK parliament on Monday that data-gathering centre GCHQ had any access to US spy programme Prism.
However, Hague told MPs in a statement that GCHQ did not use its relationship with the US to "get around" UK law.
"It has been suggested that GCHQ uses our partnership with the United States to get around UK law, obtaining information that they cannot legally obtain in the United Kingdom," said the foreign secretary. "I wish to be absolutely clear that this accusation is baseless."
"Any data obtained by us from the United States involving UK nationals is subject to proper UK statutory controls and safeguards including the relevant sections of the Intelligence Services Act, the Human Rights Act and the Regulation of Investigatory Powers Act.
"Our intelligence sharing work with the United States is subject to ministerial and independent oversight and to scrutiny by the intelligence and security committee," he continued. "Our agencies practice and uphold UK law at all times even when dealing with information from outside the UK."
The foreign secretary said a combination of a robust legal framework, ministerial responsibility and scrutiny from the intelligence and security committee should give the public a "high level of confidence" that the system works "as intended".
The statement was made as pressure mounted on government to respond to American whistleblower Edward Snowden's leaks about governments' surveillance through the spy Prism programme, which GCHQ is alleged to have had access to since 2010.
Prior to the statement, Hague told the Andrew Marr show that law-abiding citizens had "nothing to fear about the British state", while web pioneer Sir Tim Berners-Lee warned in the aftermath of the revelations that unwarranted government surveillance is an "intrusion on basic human rights". Tech giants including Google and Facebook have denied allowing governments access to their servers.
The Guardian newspaper revealed leaked US National Security Agency (NSA) data at the weekend before revealing the identity of the whistleblower - a former technical assistant for the CIA - on Sunday at his own request. Snowden told the paper he was currently in Hong Kong and hoped to seek asylum, possibly in Iceland. The Twitter hashtag #IStandWithEdwardSnowden began trending shortly after his identity became public in a show of support ahead of expected attempts from the US to have him extradited.