SCOTTISH Labour have been left reeling after a senior party member encouraged Scots to vote tactically for the Conservatives or Liberal Democrats against the SNP in certain Scottish constituencies.

Robert McNeill, a member of Labour’s Scottish Policy Forum and vice-chairman of the East Lothian Constituency Labour Party, tweeted an image of a chart showing the 16 Scottish seats in which either a Tory or LibDem candidate is better placed to defeat the SNP than a Labour candidate.

The chart carries the strapline: “Tactical Voting General Election 2015”. At its centre is a bullseye emblazoned with the words: “For all other constituencies vote Labour”.

McNeill abruptly suspended his Twitter account after the tweet, first published on Sunday, began to attract attention.

The incident is particularly embarrassing for Scottish Labour leader Jim Murphy, who has built his General Election campaign around the message that every vote for the SNP makes the re-election of the Tories more likely.

Yesterday, in an effort to hammer this message home, Murphy staged a special event in Glasgow that brought together Labour supporters who voted Yes to independence last year with Labour No voters. “Although we voted in different ways last September, we all want change for Scotland. We all care about Scotland’s future,” Murphy said.

“In the election in May we have an opportunity to shape a better future ... we need to stop the Tories? being the largest party across the UK. And the way to do that is by voting Scottish Labour.

But opposition parties were quick to capitalise on McNeill’s gaffe. “Labour’s campaign in Scotland has just imploded,” said SNP MP Pete Wishart.

“If Jim Murphy keeps Mr McNeill in his policy post, then the only conclusion people in Scotland will be able to draw is that he too wants Labour voters to cast their votes for Tories, which makes the re-election of David Cameron more likely.

“When a senior Labour member is calling for people in Scotland to vote for the Tories, it is no wonder that far more people trust the SNP rather than Labour to keep the Tories out of government.”

“The key issue in May is who will best represent the people of Scotland – the General Election is a wonderful opportunity for Scotland to have power by electing a strong team of SNP MPs to a hung parliament at Westminster.”

Jason Rose, the Green Party’s candidate for East Lothian in May, said the tweet showed how badly Labour had “lost its way”.

“A senior Labour figure from Tranent sending out a ‘Vote Tory’ message shows how badly Labour has lost its way,” he said. “This sort of ‘do as you’re told’ politics is what turns people off, and highlights the ridiculous sense of entitlement this tired, old party has in places like my home town.

“By contrast I’ve been getting a great reception in East Lothian, hearing from folk who want to vote for something positive. With policies such as a £10 minimum wage and renationalising the railways, it’s little wonder Greens are proving a real draw for former Labour voters.”

The Scottish Conservatives said the General Election should not be a “re-run of the referendum”.

“Our view is that people, regardless of which constituency they live in, should vote for the party they feel they agree with most,” a party spokesman said.

“Voting tactically can be uncertain, and we think the best thing to do is judge parties on their merits. We don’t feel this General Election should be a re-run of the referendum – it’s not a case of everyone else versus the SNP.”

Polls show the SNP is on course for a landslide victory in May, with some experts predicting the party could take as many as 40 seats.

According to research by both Ipsos MORI and Tory peer Lord Aschroft, the biggest swings to the SNP appear to be taking place in Labour’s traditional west coast and Central Belt heartlands.

McNeill’s tweet will be seen as the latest in a long of line of gaffes and embarrassing incidents for Murphy. Last week the East Renfrewshire MP visited a Glasgow hospital and declared that the cancellation rate for operations was four times that in England. Realising that this was not actually accurate, Murphy slyly deleted the related YouTube video.

Sections of Murphy’s website that included links to articles in which he backed the Coalition’s spending cuts were also deleted.

An attempt by Murphy to win back Labour voters who voted Yes in the referendum was widely mocked and even downplayed by his party. Although the name Labour for Yes was dropped, the event still went ahead.