Russian spies targeted the Democratic Party to dig up the dirt on Donald Trump

Two groups of Russian spies penetrated the Democratic Party for a year to find out more about presidential candidates

Hackers acting on behalf of the Russian secret services successfully penetrated the network of the Democratic National Committee (DNC), tapping emails and other data traffic in a bid to glean intelligence on US presidential candidates.

The DNC is the formal governing body of the US Democratic Party and claims that no private or financial details were compromised in the attack, which began last summer and was only uncovered in April when a second group sought to access the party's files on Republication candidate-elect Donald Trump.

The attack was admitted last night by Democratic Party officials. The breach was only cleaned up at the beginning of June.

The organisation became aware of a compromise in late April, when the IT team reported unusual network activity, and called in security company CrowdStrike to handle the breach. It installed logging software to get a better idea of what was happening on the organisation's network.

It claimed that not one, but two separate hacking groups working for the Russian government were behind the breach. The first, which it calls "Cozy Bear", had set up home on the DNC network last summer, monitoring email and instant messaging. The second group, which it calls Fancy Bear, blundered in in April, setting off the alarm. It had targeted research files, including all the dirt the DNC has no doubt collected on Trump - that's probably quite a big file.

It is not the only US political institution to have been targeted by Russian spies in the run-up to the comedy festival that is the US presidential election. According to reports, the networks of the political organisations of candidates Hillary Clinton and Donald Trump were also targeted, and the computers of some political action committees, which raise funds on behalf of specific candidates, had also been compromised too.

If it was Russian spies, as claimed, the collection of intelligence - and dirt - on world leaders would be one of their functions.

The attack also raises new question marks over the security of Hillary Clinton's private email server, which she used for government business when she was US Secretary of State, a position that put her in charge of foreign policy under President Obama from 2009 to 2013.

In an interview with Spanish-language US TV channel Telemundo, Clinton described the Democratic Party hack as "troubling", but asserted that her campaign had not been hacked into "so far as we know". She also came out with the usual rhetoric about being "absolutely focused" on cyber security should she be elected president in November.