Labour trails a long way behind Prime Minister Theresa May's Conservatives in opinion polls, and many within the party believe 67-year-old socialist Corbyn is too left-wing to connect with voters.
During his first campaign event for the general election on June 8, he said the upcoming poll was not a "foregone conclusion" and Labour could defy the "establishment experts", the BBC reported. "The result is not certain", she said on Friday in a speech at a GlaxoSmithKline factory in her constituency of Maidenhead.
Answering questions after her speech, Mrs May was asked whether older people can expect to see their pensions continue to rise if she wins the election as they have done so far under Conservative-led administrations.
That entails leaving the EU single market and customs union, so that the United Kingdom can impose immigration controls on EU citizens, free itself from the European Court of Justice's jurisdiction and pursue its own trade deals.
Net migration has consistently been running at around three times the government's target, with the latest figures in February putting the level at 273,000.
Mr Farron was speaking as he visited the Manchester seats of Gorton and Withington, two of a string of Remain-voting Labour strongholds in the North West of England which the Lib Dems hope to snatch from Mr Corbyn's party.
European Council President Donald Tusk, who is chairing a summit of the other 27 EU leaders on April 29 to agree on the EU's Brexit negotiating position, said he did not think the plans would be affected by the election. During this time of change for Britain we need a leader that will stand strong in the upcoming negotiations, a leader that won't crumble under the pressure of negotiating with 27 European Union nations.
The polls - admittedly not always a reliable indicator - give the Tories a 24 point lead and unless there is some sort of political natural disaster, it is hard to see how Labour can pull off a most unlikely victory.
Mark Pritchard MP, who represents The Wrekin, said: "Winning the election will strengthen the Prime Minister's position nationally and internationally". Polls suggest the party could lose dozens of their current 229 seats in Parliament.
Conservative Party chairman Sir Patrick McLoughlin then seized on the comments, insisting Mr Corbyn was sowing "chaos" which would "disrupt our Brexit negotiations".
Mr Tajani last week said his priority for Brexit was "defending the rights of our citizens" affected by the UK's decision to withdraw from the EU.