The approach came 10 days ago and was met with a sympathetic hearing from Electra's chairman, Michael Stoddart, who has been looking for ways to boost Electra's flagging share price for some time.
Brian Larcombe, 3i's chief executive, had been hoping to tie up an agreed deal by today.He sees the combination as the best way of countering American venture capitalists like Kohlberg Kravis Roberts and Hicks Tate & Muse, which are now aggressively targeting European deals.
Electra is believed to be unhappy with the 700p a share 3i has said it would be prepared to offer - even though that would represent a premium both to net asset value and to Electra's closing price on Friday of 562p.
The 3i chief executive has indicated that he would be prepared to go hostile if he cannot persuade Electra to back down over price.
Mr Stoddart believes that Electra's conservative accounting policy understates the value that could be unlocked from its large portfolio of unquoted industrial holdings when they come to be floated or sold.
He also believes that the price does not fully reflect the value to 3i of Electra Fleming, the team that manages the trust's investments, which is half owned by the trust and half by Robert Fleming, the merchant bank.
He believes that while 3i has a considerable track record in small and medium-sized deals, the group needs Electra Fleming's expertise if it is to achieve its ambition of breaking through into the really big corporate buyouts that have so far eluded it.
3i rejects claims that it has yet to pull off anything comparable with deals like the privatisation of Her Majesty's Stationery Office, or the buyout of Germany's Woolworth stores, both of which are recent Electra scalps.
Electra's bargaining position is limited. The trust is currently trading at a 17 per cent discount to net asset value. However 3i, a FTSE 100 company, has traded at or above net asset value since it floated in 1994.Reuse content