The level of spam coming from the UK has doubled since April, making the nation the fourth largest source of spam in the world.
In August, 4.5 per cent of global spam came from the UK, over double the percentage seen in April, a report from Symantec Hosted Services has shown.
The UK remains behind the US, India and Brazil in the list of top spam-relaying nations.
Similar rises to the UK's were also seen in Germany, France and Italy, meaning four of the top 10 spam sending countries are now located in Western Europe.
Overall, the percentage of spam sent by botnets has increased from 84 per cent of all spam in April, up to 95 percent in August.
The Rustock botnet kept its place as the king of spam, putting out 41 per cent of all botnet spam in August.
A significant number of unregistered botnets were also seen sending out messages, as 17.6 per cent of all spam came from these unclassified sources.
"We have seen impressive activity from the usual botnet suspects and in many cases there are likely to be newer incarnations of existing botnets that have been updated and there are also likely to be some brand new botnets that are now beginning to emerge," said Paul Wood, MessageLabs Intelligence Senior Analyst, Symantec Hosted Services.
A recent report from AVG pointed to the UK as the 30th most dangerous place to go online.
