* Customs debate is stalling Brexit talks, politics
* Minister says customs partnership still on table
* Companies signal support for Clark
By Elizabeth Piper
LONDON, May 6 (Reuters) - Britain is still weeks away from making a decision on its future customs arrangements with the European Union, a minister said on Sunday, adding fuel to a debate that is all but stalling talks in Brussels and politics at home.
After local elections last week when Prime Minister Theresa May's Conservative Party did better than many expected, how to solve Britain's new border with the EU when it leaves the bloc is increasingly a headache for her team.
May, dependent on the support of a small Northern Irish party for a majority in parliament, is under pressure from Brexit campaigners to drop what some say is her preferred option of a customs partnership to keep trade flowing freely.
On Sunday, her business minister, Greg Clark, again made the case for that partnership, saying the option had not been rejected but that ministers were working on it and another high-tech option to try to reduce any new friction at the border.
Both options have been dismissed by EU negotiators.
"I've never been so clear-eyed in my life about this. I do feel very strongly, for this reason. It is absolutely right that we should be leaving the customs union ... but what we replace it with is of huge importance," he told the BBC, denying he left a crunch meeting on customs teary-eyed last week.
Clark, who used the example of car maker Toyota which relies on components crossing borders to manufacture cars in Britain, said businesses needed the certainty of what happens next, but warned that it could take some time not only to make a decision, but also to implement it once it had been agreed upon.
"As part of the work over the next few weeks I think it would be a mistake to move from one situation and to another and to a third," he said, arguing that ministers could improve the two options while admitting they both have drawbacks.
"Whichever option is chosen it will take some time to have them put in place and available."
His message was supported by some businesses, with Adam Marshall, director general of the British Chambers of Commerce, saying that whatever the deal, the government must be driven by "practical considerations" rather than ideology.
WAITING
Britain's future customs arrangements after it leaves the bloc in March next year is fast becoming the main flashpoint in the Brexit debate, important because some fear it could usher in a return to a hard border between British-ruled Northern Ireland and the Irish Republic, possibly reigniting sectarian violence.