July 20 (Reuters) - A £167 million ($224.08 million) stake in Britain's biggest telecoms group BT BT.L was offered for sale via an accelerated bookbuild, a bookrunner said on Monday.

Here are some more details:

• An undisclosed shareholder, who launched the sale of about 85 million shares in BT, is monetizing the bulk of its position and is not subject to any lock-up on remaining holding.

• The deal is secondary, meaning no new shares are being issued and no proceeds flow to BT. The settlement is expected on July 23.

• Late last month, BT and Verizon VZ.N announced a deal to combine their international enterprise operations into a 50:50 joint venture, focussing on serving multinational clients and bringing together $4 billion in combined annual revenue.

• The sale of shares in BT represents about a 1% stake in the London-listed telecoms group, according to the bookrunner. BT has a market capitalisation of £19.76 billion, according to LSEG data.

• Shares of BT group closed 0.6% down. They have risen 6.9% so far this year.

($1 = 0.7453 pounds)