Ocado (OCDO) shares have shot up by 18.6% so far this morning after rumours surfaced that US internet giant Amazon may be plotting an approach for the UK online grocer.

Ocado shares have jumped to 287.6p this morning – having slumped to their lowest level since 2014 yesterday after dropping to 239.4p.

Talk in the City yesterday was that Amazon was considering making an offer to tie-up with Ocado to simplify their efforts to launch an online grocery business in the UK.

Ocado has been seeking deals with international grocery groups for some time and had pledged to sign a deal by the end of 2015, but no deal has yet materialised.

Ocado shares hit an all-time high of 600p in February 2014 but have subsequently slumped amid concerns about competition, primarily from Amazon, and its failure to secure international agreements.

The long-awaited entry of Amazon to the UK grocery market is strongly rumoured to be imminent.

Reports suggested that Amazon Fresh was set to launch in September last year, but the launch was not forthcoming and Amazon is still thought to be setting up its own fresh supply chain with the aim of launching in 2016.

Amazon did add grocery to its Prime Now service last year, starting in Birmingham and a handful of London postcodes.