Definition
Email jamming is a form of deception that is mostly used by civil rights activists as well as other personnel, in order to regain their privacy in internet communication from government spy networks.
To do this, users will use sensitive words and phrases in emails which in actuality are harmless and inoffensive. This is done intentionally to attract the attention of governing bodies. As a result of this the emails being sent will imply that the sender is not a threat and therefore will be placed on a list that exempts their emails from being monitored, thus having their emails remain confidential even from government agencies.
UK Act of Parliament and its Impact
In the year 2000 a new act was passed in the UK, the Regulation of Investigatory Powers Act (RIPA). This was first introduced by Jack Straw and later extended by David Blunkett. This regulation allows UK intelligence authorities to intercept and interpret the contents of emails sent by potential criminals. Since then email jamming has increased greatly in the UK.
References
http://www.knowledgerush.com/kr/encyclopedia/Jamming/
http://www.e-mailaccount.co.uk/jamming.htm
http://www.ucertify.com/article/what-is-email-jamming.html