The Charity Commission has said it will include charities' explanatory notes in its "user-friendly" web version of the Standard Information Return.
The Government's Strategy Unit report last month proposed that all charities with income above £1 million complete an annual information return, including fundraising ratios with an explanatory text.
Charity lawyer Alistair Collet, partner with Farrer and Co, said this could lead to league tables by the back door if charities' information appears without explanation of high or low fundraising ratios.
"The key point is that putting something in a user-friendly form, if this strips it of explanatory information, is likely to end up almost immediately as a league table. I don't think the Charity Commission is anxious to produce a league table, but one could emerge because of what it does," he said.
But the Commission has sought to reassure the sector that it will not simplify charities' returns.