17/06/2016 10:21 BST

Jo Cox, Birstall MP, Was Set For Security Upgrade After 'Three-Month Hate Mail Campaign' Before Murder

The hate mail was not connected to the man arrested over her death.

Police were reportedly set to increase security for MP Jo Cox after she received a three-month barrage of hate mail before she was murdered on Thursday in West Yorkshire. 

The mother-of-two was punched and kicked to the ground by her attacker as she walked to her constituency surgery in Birstall around 1pm, before being shot three times with an antique-style weapon and stabbed by a man who was heard to say "Britain first". The party has distanced itself from the attack

Police later arrested far-right supporter Thomas Mair, 52, who has a history of mental illness. 

Yui Mok/PA Wire
Police were reportedly set to increase security around murdered MP Jo Cox following a three-month hate mail campaign

The Times reported Friday that Cox, 41, had been harassed by a stream of messages in recent months and as a result police were looking at - but were yet to - increase security at her surgery and at her houseboat in London. 

The newspaper said there was no link between the hate mail and Thursday's killing, which was the first murder of an MP in more than 25 years. Ian Gow, a parliamentary private secretary to Margaret Thatcher, was killed in 1990 when the IRA exploded a bomb under his car, outside his home in East Sussex. 

Cox reportedly "thought little of" the hate mail until the volume and frequency increased, a source close to Cox's office told the Times. A man was said to have been cautioned over the communications. 

Nigel Roddis/PA Wire
Forensics officers at the scene of the murder in Birstall, West Yorkshire 

MPs are said to have expressed concerns about security at their surgeries since Labour MP Stephen Timms was attacked by an Islamic fanatic in 2010. A report for the House of Commons Administration Committee last August revealed that security was a particular concern for women MPs, Sky News reported. 

Liberal Democrat Nigel Jones, now a peer, was wounded and his aide Andrew Pennington was stabbed to death in a sword attack at the party's office in Cheltenham in 2000. 

In the wake of the murder, Sky News reports that MPs have been told to contact police to review their security, with Tory chief whip Mark Harper and Labour counterpart Dame Rosie Winterton, issuing the advice. 

Yui Mok/PA Wire
Cox was said to have "thought little of" the hate mail until the volume and frequency increased

Conservative MP James Berry told the broadcaster the chief whip had given "us very similar advice" to the Labour chief whip. 

He said the "main concern" was around public events and surgeries. 

The attack came a week after Tory whip Gavin Barwell was threatened outside his constituency office in Croydon.

And in the hours following Cox's death, a man was reportedly detained by police over an abusive phone call made to the office of MP Ben Bradshaw.

Bernard Jenkin, MP for Harwich and North Essex, told Sky he no longer meets constituents alone, saying: "There have been times when I have suddenly felt I am in danger."